Features Durable Construction: Made of high impact plastic, this tool offers exceptional strength and wear resistance for long-lasting performance Versatile Joint Capability: Perfect for creating edge-to-edge, T, and edge-to-corner joints, enhancing your woodworking projects' versatility Self-Centering Design: The quick doweling jig self-centers on boards, ensuring precise and fast dowel joint alignment for efficient work Efficient Double Drilling: Drill both parts of the joint consecutively in one jig fitment, achieving professional results without the hassle Compatible with Most Drills: This woodworking tool is suitable for use with a wide range of hand and power drills, maximizing your tool collection's efficiency 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