Features Versatile Drill Bit Set: Includes 7 precision drill bits for various screw sizes (4mm to 10mm), ensuring you have the right tool for every project Efficient Countersink Design: Features specially designed steel countersunk holes for a perfect fit, allowing for seamless integration of screws into wood surfaces Dual Functionality: Drill and countersink wood screws simultaneously without the need to switch bits, saving you time and enhancing productivity Adjustable Depth Control: Easily adjust the drilling length for different screw sizes by simply loosening and tightening set screws, providing flexibility for various applications Enhanced Chip Removal: The 5 flute design allows for quicker wood chip removal, reducing clogging and ensuring a smoother drilling experience every time Features: 1、The set includes drill bits for drilling pilot holes, screw sizes are m, 4mm, 5mm, 6mm, 7mm, 8mm, 10mm. 2、Specially designed steel countersunk or countersink guide holes. 3、Drilling and countersinking wood screws without changing drill bits. 4、Just loosen and tighten the set screws to adjust the drilling length of screws of various lengths. 5、5 flute design for quicker wood chip removal during use. 6、Smooth and flat countersunk, and the nut is ly embedded in the of the workpiece. Specification: Item Type: Countersunk Drill Bit Dimension: m x 60mm(L) Chamfer Diameter: 15.8mm 4mm x 75mm(L) Chamfer Diameter: 15.8mm 5mm x 85mm(L) Chamfer Diameter: 15.8mm 6mm x 9m(L) Chamfer Diameter: 15.8mm 7mm x 100mm(L) Chamfer Diameter: 15.8mm 8mm x 110mm(L) Chamfer Diameter: 18.8mm 10mm x 120mm(L) Chamfer Diameter: 18.8mm Shank: 1/4 hex shank Size Error: ±2mm Package List: 7 x Countersunk Drill Bit 1 x Hex Wrench Package List 7 x Countersunk Drill Bit 1 x Hex Wrench