General description This AlwaysH Set of 3 Step Countersink Drill Bits is designed for precision drilling in various materials such as steel, brass, wood, and plastic. Made from high-quality HSS steel and coated with titanium, these drill bits reduce friction and heat, ensuring durability and efficiency. The unique step design allows for drilling holes of different sizes, ranging from 4mm to 32mm in diameter, without the need for pilot holes or pre-drilling. The bits automatically deburr holes as you drill, making them ideal for thin metals and other materials. Technical specifications Material: HSS steel with titanium coating Drill sizes: 4-12mm, 4-20mm, 4-32mm Length of bits: 4-12mm (Approx. 6.7cm / 2.64"), 4-20mm (Approx. 7.4cm / 2.91"), 4-32mm (Approx. 10.2cm / 4.02") Recommended speed: 250-400 RPM/min Suitable for workpieces 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