• High Speed Steel Step Drill Bits • Titanium Coated Steel • 1/4" Locking Hex Shank • 6-Step Bit (inches) - 3/16", 1/4" , 5/16", 3/8", 7/16", 1/2" • 9-Step Bit (inches) - 1/4", 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4" • 13-Step Bit (inches) - 1/8", 5/32", 3/16", 7/32", 1/4", 9/32", 5/16", 11/32", 3/8", 13/32", 7/16", 15/32", 1/2"