The CM-7M tactical gas mask is the ultimate chemical, biological, radiological, and nuclear (CBRN) defense system when used in conjunction with suitable filters or a breathing apparatus. The military-grade technology used for this full-face respirator provides comprehensive protection against the full spectrum of CBRN agents and toxic industrial chemicals in the form of gases, vapors, and aerosols. Key Benefits of the CM-7M Military-grade Gas Mask:

• Outstanding resistance against all kinds of CBRN agents, industrial toxic gases, riot control gases, etc.
• Compatible with the Scott 804442-01 spectacle kit (sold separately)
• Easy donning and doffing
• Low breathing resistance
• Fits up to 2 NATO-standard 40 mm gas mask filters (widely available with a variety of protection levels)
• Compatible with optical devices (night-vision goggles, etc.)
• Allows for safe and easy drinking during use in a contaminated area
• Comes with a pre-installed hydration system and canteen
• Compatible with CamelBak water bladders with a Type M adapter (not included)
• Sweat drainage through the exhalation chamber
• Compatible with helmets and breathing apparatuses
• High-quality speech diaphragm enables easy communication with or without communication devices.

To size yourself, it would require a device called a faciometer which is not very common. ?

Medium fits 95% of the population, so if you're an average size person, we would suggest size 2.? For smaller than average people who weigh 130lb or less, with thin faces, we would suggest size Small. For users over 250 lbs and wide faces, go with Large.

You will know the size is right if you do a negative pressure test (blocking the inhalation valve and taking a deep breath), and the mask seals tightly to your face.