A.Y. McDonald Ball Valve Curb Stops maintain their low turning torques and bubble-tight 300 psig water pressure rating due to the PTFE coated brass ball that is supported by two blow-out proof EPDM seals. The end piece joint is sealed with an EPDM O-ring and thread locker. McDonald® Ball Curb Stops offer positive shut-off from either direction and are available with a wide variety of end connections.