Contains easy closing mechanism. Plastic washers help prevent crushing the CPVC or plastic pipe and assure a floating fit. Flared edges and specially designed welding area help protect CPVC piping. Suitable for 3/4" - 2" (20 - 50 DN) steel sprinkler pipe. Combo head bolt works with slotted, hex, or Phillips drivers. Conforms with Manufacturers Standardization Society (MSS) SP-58 (Type 12).