Surprisingly these can still be bought easily on Ebay, Aliexpress etc. Many seem to be Soviet "new old stock" models (or perhaps actual new items?). This might

Surprisingly these can still be bought easily on Ebay, Aliexpress etc. Many seem to be Soviet "new old stock" models (or perhaps actual new items?). This might be explained by the fact that they've been used quite a lot in Soviet military equipment, even long after they were considered obsolete in the west.