IRWIN Tools 10234CB Unibit Cobalt Sheet Metal Step Drill Bit offers 12 different hole sizes in one single bit, from 3/16" to 7/8" in increments of 1/16". Ideal for drilling true, round holes with a smooth, clean finish in a variety of materials like stainless steel, sheet metal, aluminum, fiberglass, plastics, plexiglass, and wood. The cobalt high speed steel construction provides increased life of the cutting edge which makes it ideal for tough applications like stainless steel drilling. The SpeedPoint tip penetrates fast and doesn't require a pilot/starting hole. The 3/8" hex shank provides secure grip in the drill chuck. Permanent laser-etched sizes inside flute are easy to read for precise control during the hole enlarging process. Product made in USA.