A small light weight compressor/air pump(1) powered by two interchangeable rechargeable battery cells one powering the unit while the other is being recharged (2). The pump nozzle will be attached to a air hose approximately 1/2 to 3/8 inch in diameter. The pump outlet hole should be between 1/4 and 1/2 inch (6). Air flow i estimate at about 2 cubic feet per minute. 1 cu.ft. (0.028 Cu.m. ) minimum. (5). The hose will attach to a plastic bag that will be inserted into the cast between the stockinette and cotton padding. The plastic bag will be vented with air passages at two to three inch intervals to assure air circulation throughout the casted area.