Designed to meet the requirements of ANSI B16.33 1981, the Dresser Style 175 GTO Gas Service Valve incorporates the same complementary sealing principles as the Style 175 meter curb valve, yet offers a rated working pressure to 175 psig. Each GTO valve is 100% factory-tested at high and low pressure while in a clear non-corrosive fluid. Just as the Style 175 meter curb valve, the GTO is assembled at the factory and sealed against tampering by a spring-loaded stainless steel retaining ring, which cannot be removed with ordinary tools. It is tamper proof as specified in D.O.T. 192.363 Part C.