Nobody here speaks Russian do they?
I decided to open the little tin that came with my gas mask, and inside I found several round, clear disks and two small pieces of paper, which seemed to be instructions for use and manufacturer's info. I've heard they're supposed to be antifog lens inserts, or some kind of emergency replacement lens, but I'd prefer to know for sure. I spent some time copying the characters into Google Translate, but that didn't provide much clarification other than the fact that they were manufactured in 1972. I've made an image of the text, as I'm not sure if TWHL works with cyrillic text, and the pieces of paper were too small to get a clear enough photo with my iPod.
The top paragraph is printed on one side of one sheet, the second on the other side, and the two characters at the bottom are stamped on the tin. The second piece of paper only had the number 44 on it.
"NP"
Kuioysheva Chemical Works V.V.
Triacetate
Batch 236
6pc. set D-59
Mfg. April 1972
Tightly protects from moisture.
Grab only by the edges.
Apply antifog film on the glass (?)
Used film must be replaced with a new one.
Do not rub when cleaning the "NP" mask.
NP
44 must be the size.
And they're not radioactive, but they possibly contain asbestos.
I haven't even opened any of the russian filters.
Yeah I'm not sure I'd trust those filters, you may be better off using modern filters. If only just in case.
Otherwise, I don't know. Google learns fast