8pcs 100mm Length 1/4" Hex Shank Head BST Screwdriver Bit 2.5-12mm Set Kit Description: These screwdriver bits are adopted of S2 quality steel, which is anti-impact and tough, great wear resistant. Magnetic head, so they can fixed on the screw firmly. Features: Exquisite workmanship, each edge can be accurately locked screws, no damage to the screw, and the screwdriver head. Adopted of S2 quality steel, which is anti-impact and tough, great wear resistant. With 1/4" hex shank, they are widely used on electric screwdrivers, hand screwdrivers, electric drills, etc. There are different sizes of screwdriver bit heads, H2.5, H3, H4, H5, H6, H8, H10, H12. So is convenient to you, can meet your varied requirements. A commonly used material in hardware with high hardness, such as electric screwdrivers, hand screwdrivers, electric drills, air drills, etc.   Specifications: Materials: S2 alloy steel Type of Shank: Hex Dia. of Shank: 6.35mm (1/4 inch) Length of Screwdriver Bit: 100mm Size of Bit: H2.5, H3, H4, H5, H6, H8, H10, H12　 Content: 1 x 100mm*2.5mm 1 x 100mm*3mm 1 x 100mm*4mm 1 x 100mm*5mm 1 x 100mm*6mm 1 x 100mm*8mm    1 x 100mm*10mm 1 x 100mm*12mm Package Included: 1 Set x Hex Screwdriver Bit(include 8pcs)