Additional Details ------------------------------ Product description: John Guest 1/4" and 3/8" Union Connectors PP0408W and PP0412W. 1/4OD and 3/8OD quick connect fittings, designed to connect plastic or copper tubing. NSF 51 and NSF 61 listed. UK John Guest manufacturer. Simpy push water line in , and it will lock, unlocks without tools as well! These valves are manufactured from white polypropylene with food grade EPDM o-rings, for use with potable water.