The Kreg DKDB 3/8-inch Step Drill Bit for Pocket Hole Machines has a one-piece design which eliminates clogging and provides a much smoother and faster drilling stroke than the drill bits with replaceable center drills. The DKDB bit is made of cobalt steel that increases the bitís life. Because the DKDB bit is also 3/8-Inch diameter it can be used in any of Kregs other manual jigs as a premium replacement.