A grooved fitting, also known as a grooved coupling, has 4 things: grooved pipe, gasket, coupling housing, and nuts and bolts. The groove is made by chilly-forming (or machining) a groove at the conclusion of a pipe. A gasket encompassed by coupling housing is wrapped throughout the two pipe ends, http://hectorgoxeh.bloggosite.com/95538/how-much-you-need-to-expect-you-ll-pay-for-a-good-valves-and-fittings