Disposable cyliinders provide oxygen U.S.P. for critical medical emergencies until trained medical personnel arrive. Twin pack, 30-minute unit contains (2)-15-minute cylinders in a high-impact resistant case, oxygen mask, 7' of tubing, and a 6-liter per minute push-button regulator with contents gauge. Single pack, 15-minute until unit has one cylinger and all other contents. Complete set of instructions is included.