Master mechanic, 17/64" x 4-1/8", high speed steel black oxide drill bit, 135 split point, jobber length, st shank, 135 point angle with 4 cutting edges eliminates walking & provides fast penetration, black oxide tempering treatment reduces frictional resistance & improves chip flow, recommended for wood, plastic, wallboard, plywood, soft metals, aluminum, brass, bronze & for occasional use in stainless steel & other hard metals.