head drill bit set are made from Industrial grade alloy steel bit, hardened to reduce wear-outs Manganese Phosphate surfaces to rust, ensures their durability Can be used with electric screwdrivers, hand screwdrivers, electric drills, combination general purpose tools and any standard drill.Usually used for mechanical equipment, automobiles, motorcycles, bicycles, furniture, electronic equipment Come with a chain buckle and a secure bit holder, which can be hung on a your keychain, tool belt, making it easy to store and transport wherever you need Strong tips can easy to hold the screws and tightly absorb the screws Not easy to fall off, no slipping during use The magnetism doesn ’ t decay after multiple uses In the Following Sizes 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 5mm, 6mm, 7mm, 8mm Length: 50mm ( 2 ”) Sizes are stamped on bit and white-printed on storage for faster recognition, Manufacturer: Oxxggkao