3/8" x 1/2", Sharkbite Push Fitting x FNPT Adapter, Makes A Connection To 3/8" Pipe Using A Push Fit Connection & Then Gives You A 1/2" Female NPT Adapter On The Opposite End, Use To Join Copper, CPVC Or Pex Pipe In Any Combination With No Soldering, Clamps, Unions Or Glue, Just Insert The Pipe & The Stainless Steel Teeth Bite Down & Grip Tight, While A Specially Formulated O-Ring Compresses To Create A Perfect Seal, Disassembly Is Just As Fast Using The Simple Disconnect Tool, Can Even Be Rotated After Assembly For Easier Installation In Tight Spaces, Certified For Potable Water Supply & Hydronic Heating Applications.