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.

Scott General Service Respirator

Scott General Service Respirator or GSR, produced under license for the British army and is currently replacing the Avon S10 from service. The GSR takes two clip filters on each side of the mask and has a single visor rather than two lenses. It also contains a drinking tube.

Bulgarian PDE1

Bulgarian PDE1 Respirator. Another Warsaw Pact clone of the US M17 respirator. This one is probably the closest in design to the original M17.
Used by Bulgaria during the Cold War.