5/16"-18 TPI, 0.38 to 0.4" OD, 0.312" L, Nitronic 60, 4-Coils, Diamond Knurled, Free Running, Tanged, Screw Threaded Insert Screw Threaded Insert Type Diamond Knurled, Free Running, Tanged Nominal Diameter 5/16 Inch TPI 18 Thread Series UNC-2A External...