PEX couplings join one or two PEX sections together. The couplings have barbed male ends that are pushed into the ends of the PEX pipes before the crimp rings are fitted in place with a PEX crimping tool. These couplings are available straight, in a 90-degree elbow joint shape or in a "T" shape, which is used for joining one pipe section to another.
The PEX plug us used to seal off the end of a PEX pipe, where in the future it can be removed and more PEX piping added. The fitting is roughly half the size of a regular straight PEX coupling, with one barbed male end and the other end sealed off.
PEX Copper Fitting Adaptor
When PEX is connected to traditional copper water supply pipe, a PEX copper fitting adaptor is used. Like the PEX plug, this adaptor has one barbed male end, while the other end has a male or female end that the copper pipe slips onto or into. The copper pipe and male/female end of the PEX fitting is soldered together and left to cool before the PEX pipe is installed to the barbed end of the fitting.
PEX Male/Female Threaded Adaptors
The PEX male/female threaded adaptors have one barbed male end, with the other end having either a male or female thread. Interior threaded pipe ends screw onto the male threaded adaptors, where exterior threaded pipe ends screw onto the female threaded adaptors. If installing water lines, white sealing tape is first wrapped around the pipe threads, and if installing gas lines, yellow sealing tape is first wrapped around the pipe threads.