<Alloy steel material High Quality S2: These U-shaped bits are made of high quality S2 alloy steel material, which is commonly used in high hardness hardware. Be firmly fixed on screwdrivers: These bits are magnetic and can be firmly fixed on screwdrivers. 5 different sizes of U-shaped heads: The set included 5 different sizes of U-shaped heads, so can meet your needs at an affordable price. Widely Used: Widely used, suitable for electric screwdrivers, hand screwdrivers, electric drills, etc. Useful: It is helpful to operate electronic device, perfect for electrician work, mechanical repair. Specifications: Materials: S2 Alloy Steel Shank Type: hexagonal Head type: U shape Overall length: 50mm Stem type: 1/4'' hex (6.35mm) Size: U4, U5, U6, U7, U8 Package Content: 5 x Screwdriver Bits