NFPA self-contained breathing apparatus (SCBA) meets NIOSH CBRN standards, the most stringent certification for SCBAs. SCBAs provide the user with breathable air, regardless of the ambient atmosphere, and respiratory protection in toxic or oxygen deficient environments. Second-stage regulator or lung demand valve (LDV) protects wearers against biological and liquid chemical warfare agents, as well as alpha and beta particles. Design shifts weight from the shoulders to the hips, reducing back strain and indreasing stability. Accessories include 30-, 45-, and 60-min. cylinders, BAcomm voice amplifier and radio interface, spectacle frames for full-face masks, airline system with multi-link auxiliary hose, and AirBoss Sentinel warning system.