Most commonly used in a remote system just before the marker so that a player can shut off the air to the marker without depressurizing the entire remote system. If you need to work on your gun just pull the brass slide and your marker will degas, yet the remote system stays charged. This is a premium quality Slide Check valve made from the highest quality materials available. Aircraft grade aluminum main body and a solid Brass sliding mechanism make this the finest slide check on the market. Has 1/8 NPT female threads on both ends but comes with at male/male fitting to adapt to any set up.