Complete fourpiece countersink drill bit set. Bit sizes: 2.8 mm, 3.2 mm, 3.5 mm, and 4.0 mm. Each bit provides a 10 mm countersink diameter to accommodate common screw seating and flush mounting needs. Fast cutting with four spiral flutes. The four spirals enable quick, efficient cutting and help produce smooth countersunk holes for precise screw installation. Robust construction in aluminum alloy. The bits are designed to resist bending and wear, delivering durable performance across a range of drilling tasks. Efficient chip removal. The flute design ejects chips quickly, helping to keep holes clean and maintain drilling efficiency during work. Use scenarios Woodworking and furniture assembly: countersink holes for flush screw heads in panels, frames, and structural joints to achieve clean, professional finishes. Cabinetry and hardware installation: create flush entrances for hinges, handles, and brackets with controlled countersink depth. DIY projects and repairs: convenient for installations and repairs that require screws to sit flush with the surface, ensuring neat results.