Scubapro Air 2 Alternate Inflation Regulator Single hose configuration eliminates the need for a separate alternate air source. Fixed VIVA flow vane for safe and uncomplicated useone-hand operation for instinctive and simple operationthe self-flushing mechanism requires just one push on the purge to clear away all dirt. Classic downstream valve. Precision molded carbon fiber and technopolymer housing. Pre-tuned system.