Carbide-tipped Hex shanks fit 3/8" drill chucks and will not slip. Includes: 5/16", 7/16", 9/16", 11/16", 13/16", 15/16", 1-1/16", 1-3/16", 1-5/16", 1-7/16", 1-9/16", 1-11/16", 1-13/16", 1-15/16" and 2-1/16". Set comes in a fitted wooden case.