The ProPEX expansion heads are precision engineered for accurate expansion of UpoNr PEX-a tubing for ProPEX fittings. Featuring the auto-rotation interface for Milwaukee cordless ProPEX expansion tools, the heads are Nt only compatible with M12 , M18 tools, but also fit most UpoNr tools. Made from high strength steel, the chrome plated segments and black oxide ring combine durability and weather resistance. Color coded rings for easy size recognition add convenience.