10piece drill bit set Includes five drill bits: 15 mm, 20 mm, 25 mm, 30 mm, and 35 mm; two extension rods: 150 mm and 65 mm; a stopper; a conversion drill bit; and a hexagonal wrench. This allinone set covers common drilling needs. Thread design for efficiency: The 10 mm thread design enhances compatibility with extension rods, while the threetooth curved structure ensures even distribution, reducing tool opening and improving drilling efficiency. Carbide construction: Crafted from a steel alloy and heattreated for durability, these carbide bits are designed for longevity. They deliver neat, burr openings for professional results. Wide applications: Suitable for materials such as solid wood boards and multilayer fiberboards. Ideal for woodworking projects, installing doors and hinges, and other common tasks. Use scenarios Woodworking projects: drilling clean holes in solid wood boards for hardware installation and joinery with accurate diameters. Door installation: preparing larger holes for hinges and fittings, using the extension rods for extended reach and the stopper to control drilling depth. Furniture assembly: drilling through plywood or multilayer fiberboard for fast, precise hardware mounting and alignment.