Two MSA All Vision ammonia Respirators from the early 1940s (I assume) the head harness states the mask was patented 1921 but that's obviously not the year these were made. : r/gasmasks
Sundstrom Safety Anhydrous Ammonia Kit Full Face Mask H05-8621 - Acme Tools
Full Face Mask Respirator Defense Ammonia(Mask with 4# Carbon Box Set) : Amazon.in: Industrial & Scientific