Parker A-Lok 6SC6-316 316 Stainless Steel Compression Tube Fitting, Union, 3/8" Tube OD Union for connecting and disconnecting two pipes more easily than couplings Fitting connects to tubing on both ends Type 316 stainless steel for higher strength and greater corrosion resistance than type 304 stainless steel Hex nut construction for tighter, leak-free connections Compatible with stainless steel, copper, rigid and semi-rigid plastic tubing