3/8" Iron Pipe Size x 1/2" Copper Tube Size Brass Compression Coupling, Long Pattern Brass Body And Nuts With Rubber Gaskets, Rated At 125 PSI At Temperatures Up To 210 Degree Fahrenheit, Fits Both Iron Pipe Size And Copper Tube Size, For Use In Any Piping Or Repair Application On Galvanized Or Copper Pipe, Bulk.