Fashion Outlet 4PCS Woodworking Countersink Drill Bit Set 1/4 Hex Shank Counterbore 100% Brand New and High Quality Adjustable counter sleeve depth with wrench. Drilling length can be adjusted for various length screws simply by loosening and tightening the setscrew. Apply to with a clamp or joint drilling machine, suitable for drilling in the hard wood and wood floor, machine screw for wood screw.