Night Vision Guide for Canadian Airsofters

[pestobanana]

A lot more people are getting into night vision in the Canadian airsoft community nowadays, and many of them are sending me the same questions. I think it may benefit the community for me to write it all in one place, since the current amount of misinformation in existing "NVG FAQs" here is akin to a virgin writing a sex guide.

Now, I don't know everything about NVGs. If you have something you'd like to add, or have a correction and can verify it, then please do let me know to change it. I will try to write this in more simple terms for ease of understanding.

General Nomenclature

NVG - Night Vision Goggle
NOD - Night Optic Device or Night Observation Device
*NVGs and NODs are basically interchangeable terms to refer to night vision devices*
IIT - Image Intensifier Tube - Often just referred to as the tube, the high tech part of a NOD.
Photocathode - The screen used to convert light into electrons
Photosensitivity - How good your photocathode is at converting light into electrons
MCP - Micro Channel Plate - An electronic wafer inside some image intensifier tubes that intensifies the flow of electrons inside the the tube, improving image output.
Autogating - Sometimes just referred to as gating, it means when a tube has a power supply that turns on and off very quickly and flickers in order to improve image quality in dynamic lighting conditions.
Gain - The output brightness of the screen, just the brightness. Not to do with clarity, photosensitivity, etc.
Film - A thin layer of sintered aluminum oxide that blocks ions from the MCP from damaging the photocathode, but blocks out electrons in the process as well which is undesirable.

Generations

Night vision works by converting visible light and invisible near infrared light into electrons, and then converting those electrons back into an image at the phosphor screen.

Gen 1:

Gen 1 is bad, don't get it. The image intensification is not great and these generally don't see much without using an illuminator. The optics on Gen 1 devices are usually very bad with bad eye relief and massive fishbowling issues. Gen 1 may be useful if you play in an area where nobody has nightvision except you, but honestly you'd be better off with a flashlight.

Gen 2:

Gen 2 is improved over Gen 1, basically with the addition of a MCP. Some people throw around the term Gen 2+ but it is a meaningless made up term for marketing purposes. This is where the generational term becomes more of a "title" based on tube chemistry than an accurate representation of tube quality. Because of that, there are some very bad Gen 2 tubes and some very good Gen 2 tubes. If you are going to get a Gen 2 device, get something with a tube made by Photonis.

Gen 3:

Gen 3 is defined as having a Gallium Arsenide photocathode, which is significantly more photosensitive than previous photocathodes. Gen 3 is what you should be looking at buying. Gen 3 devices are significantly more expensive than Gen 1 and Gen 2, and generally come with fairly decent optics.

Filmed, Thin Filmed, Filmless:

Gen 3 tubes can generally be split into 3 types. Standard film non gated, thin film autogated, filmless autogated. Thin film and filmless tubes require an autogated power supply to prevent damage to the photocathode during use. Standard film tubes can have an autogated power supply, however military tubes typically do not come with a gated power supply. Standard film blocks around 50% of what you could see in order to protect the photocathode. Thin film reduces that to 70% and enhances what you can see. Filmless removes the film completely and uses other techniques to prevent photocathode damage.

Tube Specs and Tube Formats:

The most common formats are MX-10130, MX-10160, and MX11769.

MX-10130 - These are tubes for the PVS-7. Nobody really uses them in Canada.
MX-10160 - These are a standard tube format without an adjustable gain pigtail. These will fit any standard PVS-14 style housing with our without gain control. If it is put into a housing with gain control, the gain control will simply not work and will be fixed at a pre set level. Fixed gain is also known as automatic gain.
MX-11769 - These are a standard tube format with an adjustable gain pigtail. These will fit any standard PVS-14 style housing with gain control. They will not fit in housings without gain control.

Fixed Gain vs. Manual Gain - Many people think adjustable, manual gain is superior. Really, fixed gain is the same as keeping your gain cranked up the whole time, I personally don't see many reasons to turn it down and see less. Some people will turn it down to reduce eye strain over longer periods of time. Those that desire manual gain control will usually get in a monocular housing such as a PVS-14. Seeking out a binocular housing with manual gain is not recommended for most housings. The PVS-31 has a central gain control, however Sentinels, Mod3s, and similar binocular housings are not intended to have adjustable gain. There are however limited runs of housings that were made with gain knobs, but each side has to be adjusted individually - one knob for each tube - making it a generally undesirable feature.

Autogating

Gating is where your power supply turns the unit on and off very rapidly. It is desireable but not a necessity. A common misconception is that autogating prevents damage from light damage. It does not, though it does reduce the effects of high light environments. Autogated tubes can be burned through laser damage or prolonged light exposure in the same manner that non gated tubes can. What autogating does to very well, is it reduces bloom from light sources, and improves image quality in high light situations. It is a desirable feature in dynamic lighting environments such as urban combat and CQB where there are lots of street lights, flashlights, kill lights, etc. It is far less important if you are in the woods.

OMNI Contracts

Omnibus contracts are U.S. government procurement contracts. You will often hear people throw the term OMNI 1 through to OMNI 8 when they talk about a tube. Each contract had their individual tube specifications, however the public seems to correlate them to this general chart:

https://www.ar15.com/forums/armory/U...ces/18-317705/

Do note though, that these are minimums, not averages, so for example even though the minimum specifications for an OMNI 8 tube are lower than the minimum specifications for an OMNI 7 tube, there are tons of OMNI 8 tubes that greatly surpass the performance of most OMNI 7 tubes.

Here are the specs that should be important to you when selecting a tube, and my opinions on what I would consider good:

SNR - Signal to Noise ratio - Basically the amount of image your tube provides compared to the random scintillations generated by the MCP. Higher is better. Anything above 20 is decent, 25 is great, 30 or more is excellent but extremely hard to find in Canada. Most people will not be able to discern the difference except in extreme low light conditions.
Resolution - Measured in lp/mm or lpm, meaning lines per millimetre. Higher is better. 57 lpm or lower is considered shit, 64 lpm is considered standard, 72 lpm is considered excellent.
Photocathode Sensitivity - How good your photocathode is at converting photons into electrons. higher is better. 1600 is okay, 2000 is great, 2500 is phenomenal.
Halo - When you look at a light source, anything from a lit cigarette to a street light, you will see a washed out glow around the light source. I believe the size correlates to the distance between your photocathode and the MCP. Smaller is better. 0.7 is excellent, 1 is average, 1.5 is bad.
EBI - Equivalent Background Illumination - This is the measure of how much output your system gives with no input. In other words, it tells you how bright absolute darkness will look in your tube. This is important in extreme low light conditions because it determines how much visual contrast you will have in extreme low light, and the minimum light conditions your tube requires to produce a discernible image. Less than Anything less than 1 is good, more than that is bad.

Phosphor Screen and Image Colour

Most tubes give a green image. Some people are okay with green, to others it causes eyes train, which is why some people add filters to change the colour to be gentler on the eyes. The downside is that filters reduce the image brightness and clarity.

While it isn't new technology, in recent years white phosphor screens have become more popular. They are in really baby blue and not white, but they are much easier on the eyes. There are some very high quality white phosphor tubes, and some pretty bad ones. Remember that white phosphor tubes only refer to the colour of the phosphor screen and in no way correlate with the quality of the tube itself.

[pestobanana]

Avoid buying from places like GSCI, Alpha Optics, etc. Surprisingly, the best place to get NVGs and related devices in Canada is here through the ASC classifieds, as some users have huge collections of NVGs and related kit, and others buy and sell once in a while.

The current average price of a relatively new, thin film, autogated PVS-14 in Canada is roughly $4000. Used or lower spec ones are typically $3500, some janky ones are around $3000.

Legality

Nightvision is legal to own in Canada, however it is export restricted from the United States without paperwork. Therefore, you should buy from within Canada.

Mounting and Systems

It is generally advisable to use a head mounted system. If you get a scope, are you going to walk around with your gun shouldered?

To put the a NOD in front of your eye, you generally need the following: A helmet, a shroud, a mount, and an arm if you are using a monocular.

Helmets

While you don't necessarily have to use a helmet, you can use a nightcap or skullcrusher as well, the helmet is the most popular. Skullcrushers are uncomfortable. The Crye nightcap is okay and functions like a helmet, it has padding underneath the shroud and has velcro for counterweights.

With helmets, it is generally advisable to use a reputable brand of helmet. Clone helmets work, but would you trust several thousand dollars of your gear hanging off a cheap helmet?

The most popular helmets are the OpsCore bump, and Team Wendy bump. They are both plastic bump helmets with integrated, non removable shrouds. It is also recommended to use a counterweight on the back of your helmet so that the front does not slide down over your eyes when you are trying to use your NOD.

Shrouds



The shroud is the interface on the front of the helmet where the mount secures to your helmet. Most bump helmets have shrouds molded into the front face of the helmet, however ballistic helmets use other methods for attachment. There are old school ratchet attachments and single hole shrouds, however you should stick to the standard triangular 3 hole shroud that has one hole at the top, one hole bottom left and one bottom right. These are screwed into the helmet shell.

The most common shrouds are the OpsCore VAS, OpsCore Skeleton, and Wilcox L4 shroud. They are all pretty much the same thing, I prefer the OpsCore Skeleton shroud since it is made of one piece of metal instead of plastic with a metal insert.

Mounts



Mounts attach your NOD to your shroud and flip your device up and away or down so you can see through them. Mounts are either Force to Overcome (FTO) meaning they use detents and are flipped up and down by force to overcome the detents, or are push button mounts that use a push button to release the swing arm mechanism.

Mounts are generally bayonet, ANVIS, or dovetail. Bayonet is old, shitty, wobbly, but works. ANVIS is for aviation style mounts only, and is proprietary because the power runs from a battery pack, through the mount, and powers the NVG. ANVIS stuff kinda sucks so stick to dovetail. Dovetail is more or less the standard. It uses a dovetail shoe and is generally a stable and secure mounting surface.

Mounts attach either to arms if you have a monocular, and directly to your NVG if you have a binocular setup, or a monocular setup with a built in dovetail such as a PVS-18.

The most common mounts in Canada are the USGI Rhino, Wilcox G24, Norotos AKA2, and Norotos INVG.

The USGI Rhino is a FTO mount and uses a bayonet mount that is meant to interface with a USGI J Arm or a PVS-7. This mount is cheap, it sort of works, wobbles like crazy, and should be avoided. All other mounts mentioned use the dovetail interface.

The Norotos AKA2 is available in FTO or push button. It is an excellent mount. This mount can store the NVG in front of the helmet or above the helmet.

The Norotos INVG is a FTO only mount and is meant for use with monoculars. It allows you to rotate the NOD after it is flipped up so that it is stored closer to the helmet, allowing for a more relaxed balance and lower profile. Basically useless feature if you run binoculars.

The Wilcox G24 is similar to the AKA2 but is only available in push button. it only flips the NOD out in front of the helmet, but does so in a much lower profile manner than the AKA2. Wilcox mounts are notorious for developing wobble over time due to the pin system used to lock the push button. The G24 family of mounts are my personal preference. I run a G66 and G30, basically G24s with a built in shroud and lanyard that is more stable, lower profile, and lighter than a conventional setup but costs $$$$.

Arms

Arms attach your monocular device to your mount, and generally allow you to swap from left handed to right handed use.

USGI J Arm

This thing uses the bayonet adapter and pairs with the USGI Rhino. Wobbles like crazy, generally known to be shit, but works if you're on a low budget.

Norotos DDA

DDA stands for Dual Dovetail Adapter. It is a solid block of plastic with a screw that attaches to your monocular, and has one dovetail on each side so you can use one attachment for right eye, and you simply remove and use the other dovetail shoe for left eye. It is the most stable of the arms, however it lacks any vertical adjustment, and only the newest versions have horizontal adjustment - and only on one side. The other side is non adjustable unless you remove both shoes and switch them around. The older DDA is completely non adjustable. I don't like the DDA because it blocks a lot of the field of view on the non NOD eye, and swapping sides in the dark isn't as easy as the push button on the Wilcox offering.

Wilcox J Arm

The Wilcox J arm is basically a swing arm that screws into the monocular. It is adjustable vertically and horizontally by adjusting the angle of the swing arm. The swing arm is held in place by a push button, that is used to switch from one side to the other, which is convenient for CQB situations.

Optics

To aim your gun, you will need either a NVG compatible optic, or a laser. Most airsoft optics will be too bright on the lowest setting to be usable under NVGs, however some clones will work.

For optics, I would recommend Holosun if you are on a budget, or Aimpoint and EOTech if price is not an issue. While I run both Aimpoint and EOTech, I prefer Aimpoint due to its simplicity. However, one big advantage with EOTech is when you are transitioning from NVG optic to regular optic, it can be done so with the press of a single button, whereas with an Aimpoint you have to find the knob, and adjust it to the desired brightness.

You can look through a NVG compatible optic with your NVG as if it were a normal optic.

Lasers and Illumination

Lasers are not absolutely necessary, but are definitely cool. For airsoft in Canada, game hosts generally require eye safe IR (infrared) lasers. Eye safe IR lasers have a power output of 0.7 mW or less. The power has to be extremely low as the human eye will have no natural blink reflex, since it cannot see the laser. Do not use clone lasers such as the G&P DBAL, they are not eye safe. Some people will say they can modify them to be eye safe, but that is up to your local game host whether or not that will be recognized, as its the same reason you aren't allowed to bring shit like home made pyro.

The quality or "gucciness" of the laser doesn't really matter that much for airsoft, since it would have to be a really, really shitty laser to not work past 100m which is more than any airsoft engagement realistically takes place.

The most common lasers are Lasermax and Crimson Trace lasers for those who just want something cheap. People that want operator points will look at Steiner Optics and L-3. Steiner's CQBL, DBAL I2, and DBAL A3 seem to be the most popular. Some people also like the L-3 ATPIAL-C, which is the civilian eye safe version of the military PEQ-15.



Some laser devices have built in illuminators such as the PEQ-15, and DBAL A3. These are lower power than floodlights, but help with target identification. Do note though that while most full power illuminators are focuseable, many eye safe illuminators are non focuseable to prevent the illuminator from being focused into a non eye safe beam. The ATPIAL-C is an example of this, whereas the full power PEQ-15 has a focuseable illuminator.

Floodlights are basically infrared flashlights. As far as floodlights go, the most common ones are the Surefire Vampire series, and some of the Inforce light offerings. Inforce is cheap and works, but forces you to use the existing switch. Surefire is more expensive, but gives you the freedom to use a remote switch.

Housings

There are tons of different housings on the market and its very confusing, I will touch on the ones I have experience with or know something about. If you have direct experience you'd like to add, please share.

Monoculars:

PVS-14

Standard, most common monocular housing, adjustable gain. Made of injection molded plastic, relatively durable. Has a built in IR illuminator and is a good all 'round housing. Several battery compartments available ranging from 2 AA to single CR123.

AB NVM-2AA and AB Pitbull

Aftermarket monocular housings made by AB Nightvision. NVM-2AA uses 2 AA batteries, Pitbull uses CR123, otherwise they are the same. Made of CNC machined Delrin, fixed gain. Some are made for PVS-14 optics, some are made for ANVIS optics, which are in my opinion superior to the PVS-14.

MUM-14

No experience. Lighter PVS-14 style housing.

Vyper-14

No experience. Reinforced PVS-14 style housing.

PVS-18

No experience. Monocular housing, uses PVS-15 optics which are superior to PVS-14 optics. Has a built in dovetail so does not require an arm adapter.

Binoculars:

AN/AVS-6/9

Aviation housing, fixed gain. Uses a bridge and wormdrive to adjust interpupillary distance. Made of injection moulded plastic, known to be fragile and kind of shitty. Only uses ANVIS mounts and external power sources.

PVS-15

No experience. Made of injection molded plastic, interpupillary distance adjusted via swinging pods. Durable, but heavy.

BNVD

No experience.

AI Sentinel

Adams Industries looked to improve upon the AN/AVS 6/9 devices. They were sought after because the AVS optics gave a clearer image than PVS-14 optics, however AI addressed the shortcomings in durability. The Sentinel is a very durable housing made of CNC machined aluminum and Delrin. It uses a wormdrive with detents to adjust interpupillary distance. They can be made for either PVS-14 or AVS optics. Generally fixed gain, can run off a CR123 or use an ANVIS mount and external battery pack.

AB Mod3

Similar to the Sentinel, except the moncular pods can detatch from the bridge and be inserted into monocular adapters to be used as two separate monoculars for two different people. Made of CNC machined Delrin with an aluminum bridge, uses gold plated contacts from the battery to the pods. Can use one CR123 or an external power supply with an ANVIS mount. Monocular pods can only use CR123. Are made to accept either AVS or PVS-14 optics. A bit more wobble than the Sentinel, and not as durable, but this is my preferred housing.

AB RNVG

No experience. Runs off AA, meant to be more rugged and compete with the Sentinel.

ACT DTNVG

Made in Luxembourg, each pod can flip up individually. Pods turn off when flipped up. Fairly lightweight, can be made for either PVS-14 optics or AVS optics. Fairly expensive, and durability of the pod hinge joints is a concern.

L-3 PVS-31

Non serviceable, made of injection molded plastic. Uses GPNVG optics. Very clear image, but don't count on getting one as these are restricted to military, law enforcement, and cool guys only.

[pestobanana]

Reserved

[Gato]

[AnthonyG]

MX-10160 Tubes

MX-10160 - These are a standard tube format without an adjustable gain pigtail. These will fit any standard PVS-14 style housing with our without gain control. If it is put into a housing with gain control, the gain control will simply not work and will be fixed.

The gain control is fixed in the sense that the gain knob does not function with a 10160 tube. I would clarify that with MX-10160 tubes gain control is automatic, and managed internally by the image intensifier. I think most people who are new and looking to buy a unit by default assume manual gain is what they want, when in reality auto-gain is equally as good, and can even save you from having to busy your hands with extra controls.


EBI

One spec to add that no one ever talks about, EBI: Equivalent Background Illumination. It is somewhat of a sleeper spec that often is overlooked or not measured at all on some spec sheets.
Common description found on the internet:

The EBI level determines the lowest light level at which an image can be detected. Below this light level, objects will be masked by the EBI.

This is a pretty good description. From personal experience I would describe it as the amount of contrast perceived in the darkest portions of an image. A tube with high EBI (less favourable) will mask out detail in the darkest spots, rendering details as grey, while a tube with low EBI (more favourable) will be able to resolve an image in darker light levels. In some instances, a tube with extremely low EBI can match or even outperform a tube with 3-4 points higher SNR. That said for the average airsofter, the consensus when prioritizing specs seems to be:

1. Signal-Noise
2. Resolution
3. Photocathode sensitivity
4. EBI

Gen 2 vs. Gen 3?

Gen 2:

Gen 2 is improved over Gen 1, basically with the addition of a MCP. Some people throw around the term Gen 2+ but it is a meaningless made up term for marketing purposes. This is where the generational term becomes more of a "title" based on tube chemistry than an accurate representation of tube quality. Because of that, there are some very bad Gen 2 tubes and some very good Gen 2 tubes. If you are going to get a Gen 2 device, get something with a tube made by Photonis.

Gen 3:

Gen 3 is defined as having a Gallium Arsenide photocathode, which is significantly more photosensitive than previous photocathodes. Gen 3 is what you should be looking at buying. Gen 3 devices are significantly more expensive than Gen 1 and Gen 2, and generally come with fairly decent optics.

The Gen 2 vs Gen 3 question is one of the most common I hear people ask. For those doing research, understand that tube chemistry is almost irrelevant at this point. What matters is specs and actual tested performance. For posterity I’ll link to some great comparisons by people who know way more than any of us:

NV Picture Comparison: Photonis XR5 vs. ITT Gen 3 Omni VII vs. L3 Gen 3 Filmless
4G vs Gen3 ( S/N around 28:1 both tubes )

[pestobanana]

I originally chose not to include EBI on a general guide, because I believe PC sensitivity to be of much more importance, and higher PC sensitivity tends to lead to higher EBI, and vice versa. However, thank you for your input, I will add EBI and make some other amendments/additions. This thread is still a work in progress, lots of shit I haven't had time to write up yet.

[mcguyver]

I use manual gain to brighten an image enough to see details before they are washed out by noise. It does help in low ambient IR areas so that I don't have to bang away with IR and send out a big damn beacon for everyone with NV. Totally useless for real door-kickers who never face adversaries with NV, but airsoft is completely different.

[pewpew69]

Originally Posted by pestobanana

Avoid buying from places like GSCI,

I was thinking about saving up to buy some PVS31s from GSCI. Why do you recommend to avoid them?

[ThunderCactus]

Well, you could get a GSCI base model crap gen2 PVS31 for $10,500, OR you could buy a far superior MOD3 bino with excellent gen 3 tubes for the same price on ASC if one happens to be available.

Lenses are also worth considering.
For example, the difference between a $2000 gen 2 monocular and a $1200 gen 2 monocular might not JUST be the tubes, or markup.
I know the night optics D300 line specifically uses even lower quality lenses on the cheaper MS series than they do on the HP series.
I know the GSCI PBS-14 and PVS14C lenses both fishbowl.

[riley_A]

Originally Posted by ThunderCactus

Well, you could get a GSCI base model crap gen2 PVS31 for $10,500, OR you could buy a far superior MOD3 bino with excellent gen 3 tubes for the same price on ASC if one happens to be available.

Lenses are also worth considering.
For example, the difference between a $2000 gen 2 monocular and a $1200 gen 2 monocular might not JUST be the tubes, or markup.
I know the night optics D300 line specifically uses even lower quality lenses on the cheaper MS series than they do on the HP series.
I know the GSCI PBS-14 and PVS14C lenses both fishbowl.

Can confirm this. Had a pbs-14 with a photonis XR-5 tube in it a while back. Excellent tube, but I for sure wasnt getting its full potential because of the lesser quality glass that came with the housing. Also the value of what you can get brand new from GSCI is far less than the value of some of the new or lightly used units that frequently pop up here in the classifieds.

[pestobanana]

GSCI generally doesn't have super high end stuff, and for the stuff that they do have, the performance to cost ratio isn't anywhere near what you can get used off this forum. Their PVS-31s aren't even real PVS-31s. Not even close.

[pewpew69]

I had no idea they were such crap quality. Thanks for clarifying guys. If I'm going to spend 10 grand on something I would expect it to be really good quality.

I was originally looking at these ones in 4G:
http://www.nvoptics.com/pvs-31c-mod.html

Where do the good ones on here come from? I'm assuming from the US? From what I understand companies in the US like TNVC have the best stuff.

[riley_A]

Originally Posted by pewpew69

I had no idea they were such crap quality. Thanks for clarifying guys. If I'm going to spend 10 grand on something I would expect it to be really good quality.

I was originally looking at these ones in 4G:
http://www.nvoptics.com/pvs-31c-mod.html

Where do the good ones on here come from? I'm assuming from the US? From what I understand companies in the US like TNVC have the best stuff.

As far as gen 3 devices go, yes the US offers the most advanced tubes and devices currently. However, you cant buy most night vision devices from the US because of ITAR restrictions and other export restrictions surrounding military equipment. If you're willing to spend a bit more than 10k theres someone in the Canadian Gear Sales and Discussion facebook group selling a set of sentinels with pinnacle tubes for just over 11k
Deals like that often pop up in the classifieds here as well

[pewpew69]

I have seen a few of them here actually. I guess what I'm wondering is are those ones (sold here and on facebook) still under ITAR meaning I wouldn't be able to take them into the US or outside of Canada.

I think I saw on GSCI that their goggles are not ITAR so they can be transported around.

I assume those on here and those facebook groups were illegally taken from the US to Canada or perhaps they got some kind of export permit (of course this is a public forum so if what I am asking is illegal then send me a PM, I am just not sure what the laws are and want clarification).

I have read on a RS forum that ITAR restrictions will also be changing soon.

[riley_A]

Originally Posted by pewpew69

I have seen a few of them here actually. I guess what I'm wondering is are those ones (sold here and on facebook) still under ITAR meaning I wouldn't be able to take them into the US or outside of Canada.

I think I saw on GSCI that their goggles are not ITAR so they can be transported around.

I assume those on here and those facebook groups were illegally taken from the US to Canada or perhaps they got some kind of export permit (of course this is a public forum so if what I am asking is illegal then send me a PM, I am just not sure what the laws are and want clarification).

I have read on a RS forum that ITAR restrictions will also be changing soon.

When people outside of the US advertise devices as ITAR free they're implying that they are purchasable by individuals outside of the US. However many "ITAR-free" devices will still fall under ITAR restrictions if they were to be brought into the states. When dealing with ITAR it does matter what the place of origin of the item was, all that matters is whether or not the device falls under ITAR restrictions when you try to leave the US, even if you brought the device in legally. So even though GSCI advertises their devices as ITAR free, if you brought most of their devices to the states you technically would not be able to bring them back out without an extensive amount of paperwork that is difficult to obtain.

Regarding the devices that you'll find here in Canada, you'd be hard pressed to have someone tell you how exactly those devices came into their possession. I like to assume that the devices were acquired legally, but we're in no position to accuse someone of illegally importing/exporting devices. Unless something is unquestionably stolen then I wont worry about it.