A family of threaded check valves for installation in fittings or manifolds is offered by O'Keefe Controls. Valves are available in all-metal construction or with an optional elastomeric thread seal; body and internals are brass or stainless steel. Thread sizes range from 6/32 to 7/16•20. The valves are suitable for use with liquids or gases in pneumatic or hydraulic circuits to allow free flow in one direction and are easily installed or removed.