A
slide check is a valve used in
pressurized systems that lets
air out ahead of it (the destination) while keeping pressure intact from behind it (the source). Slide checks are commonly used in
paintball, mostly in
remote propulsion setups, to cut air off from the
gun while keeping the remote pressurized. Slide checks are also useful when working with high pressure systems, such as hydro testing or audible air or CO2 leaks as you can rapidly apply pressure and release it without the frighting "pow" or projection of hoses with QD male {quick disconnect} fittings causeing a dangerous hose whip motion