Ball Style Valves Flare & Compression Outlets A.Y. McDonald Ball Valve Corporation Stops come standard with 360? operating head and are designed for low turning torques and high pressures (300 PSIG). The PTFE coated ball is supported by two blow-out proof EPDM seals. The end piece joint is sealed with an EPDM o-ring and thread locker. There is no metal-to-metal contact which causes high torques. The bubble-tight feature at 300 PSIG makes these valves a better choice than a plug valve when test or operating pressures over 100 PSIG are expected. All McDonald Ball Valve Corporation Stops are available with a wide variety of end connections. They are made in the United States of America and are manufactured to meet or exceed the AWWA C800 (latest revision) standard, except where noted.