1/4"-28 TPI, 0.306 to 0.326" OD, 0.375" L, Nitronic 60, 8-1/4-Coils, Diamond Knurled, Free Running, Tanged, Screw Threaded Insert Screw Threaded Insert Type Diamond Knurled, Free Running, Tanged Nominal Diameter 1/4 Inch TPI 28 Thread Series UNF-2A...