An airbag, A.K.A. a Supplementary Restraint System (SRS), an Air Cushion Restraint System (ACRS), or the Supplemental Inflatable Restraint (SIR) is a flexible membrane or envelope. Air bags are most commonly used for cushioning, in particular for rapid inflation in the case of an automobile collision. The number of lives saved by air bags is hard to pin downoun One study, cited below, puts the number at just under 400 per year (6000 total), and another study indicates that air bags reduce fatalities by 8% when seatbelts are wornoun