1/4"-28 TPI, 0.306 to 0.326" OD, 0.25" L, Gray, Dry Film Lubricant, 304 Stainless Steel, 5-Coils, Diamond Knurled, Free Running, Screw Threaded Insert T1191-4CW250 Screw Threaded Insert Type Diamond Knurled, Free Running Nominal Diameter 1/4 Inch TPI 28...