Master Mechanic, Bulk Pack, 21/64" x 4-5/8", High Speed Steel, Black Oxide Drill Bit, 135 Split Point, Jobber Length, Straight Shank, 135 Point Angle With 4 Cutting Edges Which Eliminate Walking & Provide 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.