Master mechanic, 7/16″ x 5-1/2″, high speed steel black oxide drill bit, jobber length, 3/8″ 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.