For use with plastic, stainless steel, copper and other tubings. Leak-proof and corrosion-proof. Simple to install: just cut tubing end square, insert into fitting without disassembling and tighten ferrule nut for seal. No flaring required. Molded of White Polypropylene, Kynar (PVDF), Nylon and Celcon (Acetal). Note : When soft tubings such as Vinyl or Polyurethane are used, Tubing Inserts should be added.