The NBC-77 SOF 40mm gas mask filter canister, in combination with a full-face mask, mouthpiece assembly, or PAPR, reliably protects air passages against a wide range of harmful and highly toxic substances including all known CBRN agents.

The filters are produced with standard round threads according to STANAG 4155 (EN 148- 1)- Rd 40x1/7". The filter components are made of hard plastic. This results in a very robust product that is extremely durable against shock and impact damage in operational use.