Spare Air Model 300 Package Kit 3.0 cu ft w/ Free DiveCatalog's Safety WhistleThe Spare Air Model 300 Package Kit provides 3. 0 cu ft of emergency breathing gas for scuba divers. Designed for recreational diving, this compact system remains unobtrusive while offering a reliable surface ascent option in an emergency. The kit includes Spare Air, a holster, a safety leash, a refill adapter, and the DiveCatalog orange whistle with lanyard for signaling. Specifications at a glance include a maximum capacity of 3. 0 cu ft 85 liters;