Any idea on what these are:

Attached File


Here's the description:

Gas mask filters?

OTK is Russian stamp, but seen them as surplus from former combloc countries.

And the NATO description would contradict the Russian marking. They are $12 a piece so I have a few on the way for curiosity sake.

It'd be nice to know what they can actually filter out.

Did they show up? Any good?

They did show up. Near as I can figure, they are not Israeli and are most likely the combloc that will fit in NATO masks but weren't technically NATO spec. Additionally, there's enough of a chance that they may have asbestos in them that on top of being expired, they probably would only be used in a situation that I'd describe as "You're really going to die right now if you don't try this and you've got nothing else left."

Strangely enough, the only "knowledgeable" source for filter information of this type that I was able to find was a British guy in his 20's if I had to guess, who seems to be absolutely invested in all sorts of masks.

Thank you sir. Trying to find a replacement filter for my son and his new mask. I don’t know anything about them just want something safe for him

MOF-4 are Czech or Czechoslovakian.

https://gasmaskandrespirator.fandom.com/wiki/CM-4