6 most commonly-used sizes to satisfy all your needs. This drill bits set fits the majority of power drill currently on the market and come with a portable plastic bag for easy storage and organization. Industry grade 6542 high-speed steel drill bit set, harder than 4241 HSS used in other similar drill bits set. These drill bits also contain 5% Cobalt, which increases wear-resistance and durability. Fully ground spiral groove design quickly decreases friction and heat for a faster and cooler drilling performance. 135-degree split point with straight shank prevents walking and makes drilling precise and faster. No center punch is needed. It is suitable for cutting hard metals, such as stainless steel, steel and cast iron, as well as wood, aluminum alloy and other softer metals, including tiles, concrete, ceramic tiles, bricks, wood, plastics, glass, masonry, etc. The product has sharp edges and high drilling efficiency. The product center has sharp serrations, with its help, the drill can continue to drill horizontally after drilling. Usage Scenarios: 1.Suitable for holing, cutting on wood, soft metal, aluminum plate, iron, etc. 2.suitable for drilling and cut grooving processing on thin wood plate, wood, aluminum, and plastic boards Item Type: Drill Bits Material: High-Speed Steel+Titanium Plating Structure: Saw&Drill Application: Woodworking, Aluminum Alloy, Plastic Board Drilling And Cut Grooving Product specifications: 3mm, 4mm, 5mm, 6mm, 6.5mm, 8mm This is a 3 in 1 serrated drill: Function 1: Can be used as a drill Function 2: Can be used as a sawtooth groove Function 3: Can be used as a saw blade on the surface of wood Package list: 6Pcs drills Set C : 1pc (3mm+4mm+5mm+6mm+6.5mm+8mm) serrated Drill Bits Note: 1.There could be some slight differences in the color tone of the pictures and the actual item. 2.Please allow 1-2mm differs due to manual measurement, thanks. 3.If there is any problem with the product, please contact me before you leave a comment, I will do my best to solve the problem for you.Thank you for your understanding.