Scubapro Knighthawk BC w/ Air II for Scuba Divers Back flotation technology positions air bladder in the back, providing exceptional freedom of movement around chest and shoulders 3-dump deflation system enables divers to dump air from a variety of underwater positions Streamlined air cell technology Automatic volume control of air cell through compression straps Rotating Quick Release shoulder buckles and adjustable shoulder straps improve fit by following the diver's movements