This heavy-duty, cobalt-steel drill bit is uniquely designed for use with Kreg high-production pocket hole machines. The bit features a one-piece design that eliminates clogging and provides a much smoother, faster drilling stroke than drill bits with replaceable center drills. If you’re purchasing bit replacements for a DK3100 machine, be sure to also order a Left-Hand Stepped Drill Bit for the center spindle of this 3-spindle machine. For use with: For exclusive use with Kreg DB55, DB110, D3100, DK1100 and DK5100 pocket-hole machines. *This bit is not compatible with the Foreman DB210 Pocket-Hole Machine.