PEX Brass Crimp Fittings
These lead-free brass fittings can be used with any PEX or PE-RT tubing for domestic water or hot water heating systems. The fittings are inserted into the tubing and are secured with a crimp ring. A special tool is required to crimp, or squeeze, the rings onto the tubing and fitting.
Fitting size is customarily given by ID (inside diameter) of the tubing.