J Harlen Co. - Klein VACO Spiral Double-Fluted Step Drill Bit - 7/8-Inch to 1-3/8-Inch 25960
DEWALT Step Drill Bit Set, 7/8-Inch to 1-1/8-Inch (DWA1789IR) - Screwdriver Bits - Amazon.com
DeWalt DWA1784IR 3/16" - 1/2" Impact Ready Step Drill BIt – My Tool Store
DEWALT Drill Bit Set, 3 Piece, Titanium Nitride Coated, Longer Life and Better Chip Removal (DWA1790IR) - Screwdriver Bit Sets - Amazon.com
DEWALT Impact Ready 3-Piece Titanium Step Drill Bit Set - Foley Hardware
Amazon.com: SAMXY HSS Step Drill Bits 3 Piece Titanium Coated Spiral Grooved Step Drill Bit 1/4" Hex Shank Drill bit for Plastic, Wood, Metal Multi-Hole Taper Drill bit Set for DIY Lovers