IRWIN 73830 Jobber Drill Bit, Spiral Flute, 4-5/16 in L Flute, Reduced Shank, 15/32 in Dia x 1-4/9 in L Shank | M-2 high-speed steel for strength, heat resistance, and wear resistance in general drilling of wood, metal, and plastic. The 3/8 in reduced shank fits all 3/8 in drills. Jobber length.