General description This set of 3 HSS Stainless Steel Metal Countersunk Drill Bits features a unique step design that allows for drilling holes of various sizes, ranging from 4mm to 32mm in diameter. Made from high-quality M42 high-speed steel and coated with titanium, these drill bits are designed to reduce friction and heat, making them suitable for a wide range of materials including steel, brass, wood, and plastic. The drill bits automatically deburr holes while drilling, eliminating the need for pilot holes or pre-drilling. Technical specifications Material: HSS steel with titanium coating Size 1: 4-12mm (length: approx. 6.7 cm / 2.64 inches) Size 2: 4-20mm (length: approx. 7.4 cm / 2.91 inches) Size 3: 4-32mm (length: approx. 10.2 cm / 4.02 inches) Recommended speed: 250-400 rpm Suitable for materials with hardness of 25° or less and thickness of less than 5mm Usage Ideal for drilling holes in thin metals, aluminum, copper, brass, fiberglass, PVC, and more Always wear safety