Master Mechanic, 5/16" x 12", Extra Length, High Speed Steel, Black Oxide Drill Bit, 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, Carded.