The SharkBite 3/4 inch Push-to-Connect x 3/4 inch Push-to-Connect x 3/4 inch female NPT Slip Tee is used to connect copper and CPVC pipes. The Slip tee allows for the fitting to be inserted onto the pipe and then using the disconnect tool slipped back onto the other end of the pipe. This allows for up to a 2 inch section of the pipe to be removed and then repaired without having to add additional pipe. This slip tee is perfect for removing a section of pipe and adding in an expansion tank for your water heater, the FNPT Tee is threaded so you can screw in the expansion tank after installing the tee to the line.