General description This 3-piece countersink drill bit set is designed for efficient drilling in various materials including steel, brass, wood, and plastic. Made from high-quality HSS stainless steel, these drill bits are durable and reliable. Technical specifications Material: HSS stainless steel Sizes: 4mm-12mm, 4mm-20mm, 4mm-32mm Design: Triangular conical titanium with hexagon shank Installation When using the electric drill, ensure it is as vertical as possible to avoid shaking or tilting. Avoid rotating the drill too fast for optimal performance. Usage Suitable for processing thin iron plates, aluminum, insulation boards, PVC boards, and wood boards with a thickness of no more than 3 mm. The spiral design helps prevent slipping, making drilling easier and more efficient. Efficient and fast operation saves time and labor. Other information The product comes with a nylon cloth bag for convenient storage and protection, preventing loss and wear and tear.