The filter is proven to contain asbestos and getting post-soviet era filters that fit it can be expensive and difficult. I am searching surplus stores for appropriate filters right now. The members of the Warsaw pact used GOST threads on the filters which does not seal properly with NATO filters used in the west. Also I managed to get this mask for a third of the price from eBay (after shipping) back in December. The mask itself I quite like. It is comfortable and doesn't fog up too much. It does require short hair to get on properly and comes in sizes, which I don't see here.