Czech CM4 Respirator

Czechoslovakian CM4 Respirator from the late cold war (Mask stamped 1984).
It uses a 40mm filter thread and has a decent voice diaphragm and exhale valve, it also has triangular lenses. It seems like it was introduced to replace the M10m or the Model Z respirator as it's a more modern design compared to the other two.
The mask visually looks like the West German M65 and also came in a bag with German writing on it.

Czech Model Z/Polish MC1 Respirator

The Czech Model Z and Polish MC1 are identical masks. I'm unsure which I own but I think it may be the Polish model, it's quite similar to the French M51 in design.
It takes 40mm filters.

Czech/East German M10M respirator

The M10 design was cloned from the American M17 and is visually very similar, many countries inside the Warsaw Pact adopted the design but the M10 was the only mask to be used by more than one Pact member.
Both East Germany and Czechoslovakia used two variants of this mask, the OM10 which was the basic mask with a voice diaphragm, and the M10 or M10M which also included a drinking tube.