air pack(Self-contained self-rescue device, SCSR, or self-contained self-rescuer, is a portable oxygen source for providing breathable air when the surrounding atmosphere lacks oxygen or is contaminated with toxic gases, eg. carbon monoxide. A SCSR is usually a closed-circuit breathing apparatus with a chemical oxygen generator or a compressed oxygen cylinder and a carbon dioxide absorber. SCSRs are most commonly used in some coal mines, are intended for one person, and usually supply at least one hour of oxygen. They are sometimes referred to as air packs. wiki Alexander Demidov)
