Interestingly enough according to the boxes these are the C50, which is the civilan model that takes standard 40mm NATO filters. The military uses the M50, which takes proprietary filters inside the cheeks of the mask so they don't stick out and get in the way
Probably exactly it. Made by AVON they support military. https://www.grainger.com/product/AVON-PROTECTION-SYSTEMS-Gas-Mask-33X178
Interestingly enough according to the boxes these are the C50, which is the civilan model that takes standard 40mm NATO filters. The military uses the M50, which takes proprietary filters inside the cheeks of the mask so they don't stick out and get in the way