A.Y. McDonald Stop & Drain Ball Curb Stops maintain a low turning torque and bubble-tight 150 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 Stop & Drain Ball Curb Stops are available with a wide variety of end connections. All Stop & Drain Ball Valves are Directional and automatically drain from the outlet side when in closed position. This drain feature can also include a check valve so that ground water cannot back flow into the outlet side of the service line.