Various sizes to meet your needs High-quality material, HSS 4241 high-speed steel, full milling process, extended, total length 200 mm Accurate positioning, fast cutting, strong chip removal, good wear resistance, etc. Suitable for steel castings, spring steel, white steel, I-beam, ordinary steel, angle iron, aluminum, copper, wood and stainless steel 1-4 mm, etc., drilling various materials Features Twisted spiral design, easy to remove sawdust, iron filings at work. 8 different diameters available: 4 mm, 4.2 mm, 4.5 mm, 5 mm, 5.2 mm, 6 mm, 8 mm, 10 mm. For DIY projects, processes, and general construction engineering applications Our ultra-long twist drill bit is made of HSS high-speed steel and is fully milled compared to other products. It has precise positioning, fast cutting, high chip removal capacity, and good wear resistance. Specification Material: High Speed Steel Diameter: 4mm, 4.2mm, 4.5mm, 5mm, 5.2mm, 6mm, 8mm, 10mm Length: Approx. 200mm Quality: 8 pieces Note You must be very careful when drilling, due to the elongation of the product, high hardness, lack of water in the process of use or cooling of the coolant, the drill breakage is likely to occur. Take protective measures during use Package included 8 x twist drill bits