ADAPTOR 1/2 MNPT, 4 Pack | Used to transition between PEX, copper, CPVC, PE-RT or HDPE pipe to an FNPT threaded connection. The tube shall be inserted into the SharkBite PTC fitting in the first stage through a release collar and then through a stainless steel grab ring. The grab ring has teeth that open out and grip onto the tube. At the second stage the tube shall be pushed through an O-ring protector which aligns the pipe. A specially formulated EPDM O-ring shall be compressed between the wall of the fitting and the tube before the end of the tube reaches the tube stop. Only when the pipe has passed through the O-ring and reached the pipe stop shall a secure joint be created. The fitting shall be a SharkBite PTC fitting.