The RSV-1 is a modular control valve that allows a diver to switch breathing gas supplies in less than a second.

The RSV-1 is particularly useful to a Public Safety Diver utilizing a full-face mask. 

The RSV-1  allows the diver to switch to their alternate air supply without removing their mask (a valuable feature when diving in toxic or hazardous locations).

The RSV-1 allows divers the ability to assist a entangled diver by being able to pass off a spare tank or connect a surface gas supply to the RSV-1.