Abstract: A valve insert for a cylinder valve for connection an LPG tank to a gas consuming appliance comprises a body member mounted in the outlet end of the cylinder valve and a valve element slidable in the body member and cooperable therewith to control the flow of gas from the tank to the appliance. A quad ring between the valve body and valve element seals against gas leakage therebetween and provides a lubricant reservoir for lubricating the surfaces thereof, and a wiper ring downstream of the quad ring cleans the surfaces and precludes the ingress of foreign matter to the area of the gas sealing quad ring.