BOSCH CO2147B 1-Piece 5/16 In. x 4-1/2 In. Cobalt M42 Metal Drill Bit with Three-Flat Shank for Drilling Applications in Stainless Steel, Cast Iron, Titanium, Light-Gauge Metal, Aluminum - Amazon.com
Drill Hog® Cobalt Step Drill Bit Set 5 Pc M42 Spiral Step Bit Drill Ho