CBRN Gas Mask Filters

NBC-77 SOF: one filter for the unknown

MIRA rates it A2B2E2K2HgSXP3 D R under EN 14387: the four main gas types at class 2, mercury, an SX rating covering phosgene, cyanogen chloride and chloropicrin, and a P3 particle stage. It also carries a Reactor rating for radioactive iodine. It weighs 335g and keeps for 20 years in its factory-sealed bag, ideally stored between -5°C and 30°C (MIRA's figures).

ParticleMax P3: germs and dust

A P3 particle filter (EN 143) for illness and airborne germs, which also stops fallout dust. At 100g it's much lighter and easier to breathe through, and MIRA gives it a 20-year shelf life. It has no carbon, so it does nothing for gases or chemicals: keep it alongside a combined filter, not instead of one.

Using and storing filters

• Keep them sealed until you need them. MIRA's rule of thumb is about 12 hours of use per filter, and it treats an opened but unused filter the same way.
• How many: at least two per mask. To cover a three-day event, MIRA suggests six per person.
• After a real incident, replace it. Filters can't be cleaned or reused: never use compressed air or water on one.
• Oxygen: filters clean air, they don't make it. MIRA's masks are only for air with at least 19.5% oxygen.

Questions about which filter fits your mask? Ask us. We reply within 24 hours, every time.