Master Mechanic, 21/64" x 4-5/8", High Speed Steel Black Oxide Drill Bit, Jobber Length, Straight 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, Carded.