DO NOT BUY FROM "PREPPERSSHOP (dot) CO (dot) UK", THEY ARE THE WORST SORT OF SCAMMER SCUM.
Their "unused" "Polish MP5" masks are broken French ARF-A, unusable. The filters included and any spares you order are also not the modern ones in the pictures, but 80's soviet ones, full of delicious asbestos and hexavalent chromium.
On to other scammer scum, "Spanish" eBay seller of 5n11 prefilters turned out to be a chink, sent obviously fake from packaging and markings 5N11CN prefilters. But I cut one apart and it has multiple layers of non woven material of different kinds, and all in all looks like a legit 3rd party replacement with counterfeit markings and box thrown in.
I would like for any Strelok that has legit 5n11 or 5n11cn prefilters to please weight and report the weight of them (I weighted a stack of 10, to get a more acurate reading from my kitchen scale), and if I may impose further, cut one open, perhaps an used and sterilized one so it does not go to waste. I want to see how they compare.
Clone/Imitation of 3M "Dasum" gas mask also did not arrive, fake tracking info, I am in the process of making a half mask respirator out of what I can find on my garage.
Got refunds for both from eBay, which was nice. Listings where deleted, so it was no big surprise.