��Features: Brand New Drill bit for use with pocket hole joinery. Large diameter creates flat-bottomed hole. Recommended for use with corded high-rpm drills. Perfect for use with pocket hole guides like most popular kreg jigs. 3/8"(9.5mm) diameter bits step down to about 4mm. Tip Diameter: 4mm Tip Length: 14mm Shank Length: 84mm Total length:160mm This Item is for the flat step bit or 90 degree. Don't up against the wood forcefully when start up the drill! Start the drill reaches a certain speed above 500 rpm， 1500 rpm is the best! Advanced to slow down， when the front-end drill bit in half or full， then you can speed up.Package Includes �� 1 x 3/8" Pilot Twist Step Drill Bit