Gruvlok® offers a variety of pressure responsive gasket styles. Each serves a specific function while utilizing the same basic sealing concept. Proper installation of the gasket compresses the inclined gasket lips on the pipe OD forming a leak tight seal. This sealing action is reinforced when the gasket is encompassed and compressed by the coupling housings. The application of internal line pressure energizes the elastometric gasket and further enhances the gasket sealing action. Gruvlok® gasket, grade T, 2-1/2" nominal, -40 to 250 degrees F, rubber, domestic.