The Western Inert Gas "Y" with valves has a variety of uses. It is commonly used in the welding world to mix gas together such as adding a little helium into your argon for AC welding of aluminum. Some use it as a cheaper alternative to a dual flow regulator so that one side can feed the torch and the other used for backpurge welding. While this is not the most economical way to backpurge it can work for the home hobbiest. The 411 can be used in either direction.
Inert Gas RH 5/8"-18 Male to 2 Inert Gas RH 5/8"-18 Female.
CGA-032
200psi max working pressure.