Product Description Set, Wood Drilling Bit, Self-Feed, Drill Bit Material Carbon Steel, Drill Bit Size 2 1/8 in, Shank Size 7/16 in, Overall Length 5 in, For Use With Wood, Number of Pieces 1 From the Manufacturer Irwin Industrial Tools 3046011 2-1/8-Inch 3-Cutter Self Feed Bit. For fast, rough or clean and exact holes, Irwin's extensive line of woodboring drill bits provide the user with the best available tools for each application in achieving their wood drilling needs.