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- Aug 25, 2012
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I hate to bring up an old subject that may have been covered, but I did some digging and found some hard information on these, some of which, I think many people were looking for.
I spent 8 years of my life in the US Navy as an Electronics Technician, so when it comes to sorting out military documentation for others (usually higher ranking) to operate equipment correctly and effectively, I've had some experience.
I came across these glasses on Ebay for a rather reduced price. All together I paid about $11.00 US. I feel pretty confident that they are genuine, new, military issued goods. They are the dark brown variety, defined as class 4 (read below).
Now the specifics...
All of the information from here on is extracted from MIL-PRF-44366B. This is the 1996 revision, and I have no way of certifying if this is the most recent revision. Most likely, if a revision was done, it would either be unimportant for our purposes, or the standards would have become more strict. You can find this document here for your downloadable reading pleasure, or if you're having trouble sleeping at night.
AssistDocs.com
Remember: These are specifications. The manufacturer can exceed these at their leisure, but these specifications must be met.
Basically, these spectacles fall into 4 groups:
Class 1 - Clear, with ballistic protection only.
Class 2 - Smoke/grey, with ballistic protection only.
Class 3 - Green, protecting against two wavelengths of laser radiation.
Class 4 - Brown, protecting against three wavelengths of laser radiation.
Reading further down, you get to the meat of the document. There are two entire sections that spell out what the OD is for these glasses, one section for the class 3 spectacles, and another for the class 4 spectacles.
Translated, this means:
Class 3 (Green Lenses)
OD 4 @ 694.3 nm
OD 4 @ 1064 nm
Class 4 (Brown Lenses)
OD 4 @ 532 nm
OD 4 @ 694.3 nm
OD 4 @ 1064 nm
While these glasses may or may not be CE approved, I can tell you that the genuine glasses fall under strict guidelines from the US military. You don't deliver faulty goods to the military. They don't do business with someone who doesn't deliver consistantly superior products.
Now the next important part: HOW YOU KNOW THEY'RE GENUINE!!!
The MIL spec document spells out a lot! Everything from the color of the plastic earpieces to the function of the nosepiece. Everything is covered. Here are some quick details so you know you're getting a genuine product.
1. These cannot be exported outside the US. They are covered under Part 121 of the International Traffic in Arms Regulation (ITAR). If they're coming from China they're either fake, or you don't want to be associated with them.
2. The MIL spec even says what accessories they're supposed to come with! Hard case, with a hinged lid, nosepiece, neck strap, and operations manual are all standard. Missing any of these items? It had better be used!
3. If the glasses are new, they will come with everything in a cardboard box. This box will have a label on it, with an NSN number, CAGE number, descriptor and lot number. These pieces of information are essential when purchased by the military and used in their supply system. It's how they can verify that they are purchasing something that is correct for the task at hand.
4. Unfortunately, price is hard to judge with. These glasses are very inexpensive. The ones I just bought were practically on clearance. Paying $20 for the glasses and shipping is about right. Any more might be excessive.
FINAL THOUGHTS:
There is no excuse for playing with a green laser without glasses if you live in the US. For such a low cost, you not only get protection, but it is certified. You can buy Chinese and guess, or you can get these for even cheaper.
As far as other frequencies go, it may offer some protection, but I cannot be certain as to what extent. Some companies produce a wavelength graph that covers this, but there is no graph relaying this information in the MIL spec sheet. We can only take from what is stated about the specific frequencies listed.
DISCLAIMER:
As always, it is up to you to calculate how much optical attenuation is needed for the task at hand. These specific glasses are not the "best answer for all situations". Always select the appropriate eyewear for the given wavelength and power output.
UPDATE: 18 OCT 2012
I just recieved my pair yesterday afternoon. They definitely look to be ballistic and high quality, but there seems to be something lacking for laser protection. They don't seem to discolor your vision like a set of laser glasses do. Also, according to the MIL spec, they should have a marking on them (S3) to indicate the level of protection. Additionally, the label on the box describes them as "Class 2". I hope I didn't just buy some heavy duty sunglasses.
I don't have a proper LPM to calculate these out, but from what I can tell so far it looks like these might get more use on the airsoft field. They do attenuate the green to some extent, but they also attenuate sunlight like sunglasses. I'll do more research on the matter and report findings as I get them.
CONCLUSION 19 OCT 2012
Well, to keep it short, the ones I listed from the auction are not the actual laser protective spectacles. The ones I got were the class 2 grey shades. BUT, now that I have the proper NSN (national stock number), I can find the real ones and discern from the auction which ones are the correct glasses. Below I have a chart of NSNs that spell out exactly which ones do what. When buying, ask the seller to verify the NSN so you can get the proper protection.
I spent 8 years of my life in the US Navy as an Electronics Technician, so when it comes to sorting out military documentation for others (usually higher ranking) to operate equipment correctly and effectively, I've had some experience.
I came across these glasses on Ebay for a rather reduced price. All together I paid about $11.00 US. I feel pretty confident that they are genuine, new, military issued goods. They are the dark brown variety, defined as class 4 (read below).
Now the specifics...
All of the information from here on is extracted from MIL-PRF-44366B. This is the 1996 revision, and I have no way of certifying if this is the most recent revision. Most likely, if a revision was done, it would either be unimportant for our purposes, or the standards would have become more strict. You can find this document here for your downloadable reading pleasure, or if you're having trouble sleeping at night.
AssistDocs.com
Remember: These are specifications. The manufacturer can exceed these at their leisure, but these specifications must be met.
Basically, these spectacles fall into 4 groups:
Class 1 - Clear, with ballistic protection only.
Class 2 - Smoke/grey, with ballistic protection only.
Class 3 - Green, protecting against two wavelengths of laser radiation.
Class 4 - Brown, protecting against three wavelengths of laser radiation.
Reading further down, you get to the meat of the document. There are two entire sections that spell out what the OD is for these glasses, one section for the class 3 spectacles, and another for the class 4 spectacles.
Translated, this means:
Class 3 (Green Lenses)
OD 4 @ 694.3 nm
OD 4 @ 1064 nm
Class 4 (Brown Lenses)
OD 4 @ 532 nm
OD 4 @ 694.3 nm
OD 4 @ 1064 nm
While these glasses may or may not be CE approved, I can tell you that the genuine glasses fall under strict guidelines from the US military. You don't deliver faulty goods to the military. They don't do business with someone who doesn't deliver consistantly superior products.
Now the next important part: HOW YOU KNOW THEY'RE GENUINE!!!
The MIL spec document spells out a lot! Everything from the color of the plastic earpieces to the function of the nosepiece. Everything is covered. Here are some quick details so you know you're getting a genuine product.
1. These cannot be exported outside the US. They are covered under Part 121 of the International Traffic in Arms Regulation (ITAR). If they're coming from China they're either fake, or you don't want to be associated with them.
2. The MIL spec even says what accessories they're supposed to come with! Hard case, with a hinged lid, nosepiece, neck strap, and operations manual are all standard. Missing any of these items? It had better be used!
3. If the glasses are new, they will come with everything in a cardboard box. This box will have a label on it, with an NSN number, CAGE number, descriptor and lot number. These pieces of information are essential when purchased by the military and used in their supply system. It's how they can verify that they are purchasing something that is correct for the task at hand.
4. Unfortunately, price is hard to judge with. These glasses are very inexpensive. The ones I just bought were practically on clearance. Paying $20 for the glasses and shipping is about right. Any more might be excessive.
FINAL THOUGHTS:
There is no excuse for playing with a green laser without glasses if you live in the US. For such a low cost, you not only get protection, but it is certified. You can buy Chinese and guess, or you can get these for even cheaper.
As far as other frequencies go, it may offer some protection, but I cannot be certain as to what extent. Some companies produce a wavelength graph that covers this, but there is no graph relaying this information in the MIL spec sheet. We can only take from what is stated about the specific frequencies listed.
DISCLAIMER:
As always, it is up to you to calculate how much optical attenuation is needed for the task at hand. These specific glasses are not the "best answer for all situations". Always select the appropriate eyewear for the given wavelength and power output.
UPDATE: 18 OCT 2012
I just recieved my pair yesterday afternoon. They definitely look to be ballistic and high quality, but there seems to be something lacking for laser protection. They don't seem to discolor your vision like a set of laser glasses do. Also, according to the MIL spec, they should have a marking on them (S3) to indicate the level of protection. Additionally, the label on the box describes them as "Class 2". I hope I didn't just buy some heavy duty sunglasses.
I don't have a proper LPM to calculate these out, but from what I can tell so far it looks like these might get more use on the airsoft field. They do attenuate the green to some extent, but they also attenuate sunlight like sunglasses. I'll do more research on the matter and report findings as I get them.
CONCLUSION 19 OCT 2012
Well, to keep it short, the ones I listed from the auction are not the actual laser protective spectacles. The ones I got were the class 2 grey shades. BUT, now that I have the proper NSN (national stock number), I can find the real ones and discern from the auction which ones are the correct glasses. Below I have a chart of NSNs that spell out exactly which ones do what. When buying, ask the seller to verify the NSN so you can get the proper protection.
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