Trenton Pipe SS304-65914 Pipe Fitting, Class 150, Cast Stainless Steel Grade 304, Locknut, 1-1/2" NPT Female Threads A Hex Locknut locks two male threaded fittings or nipples into place for rigidity Quality Precision Investment Castings made of 304 Stainless Steel to ASTM A351 Standards USA, Standard Taper Pipe Threads, NPT-Female, to ANSI B.120.1 Standards