Dresser Style 90 Tap-N-Valve service tees offer a variety of MIPS, FIPS, weld and compression end configurations for steel x steel IPS services in 3/4″ and 1″ sizes. Style 90 tees are equipped with a tapping tool, which retains the slug cut from the main. During the tapping process, a gradual inward deformation of the abrading edges of the tool forms a positive, mechanical interlock between the tool and the slug, holding it permanently. The tapered design of the tool forms a raised conical valve seat on the surface of the main, providing a honed metal-to-metal seal for positive shut-off at any time.