Usage Tips:About this item color:red size:Length 64.5, magnetic coil diameter: 10.4cm, batch head width: 6.2cm With hex shank, they are widely used on many power drills or cordless drills. Using these screwdriver bits, drywall screw head will stretch and dimple the drywall skin, but not ruptured it. These screwdriver bits have a collar that acts as a stop, preventing the bit from following the screw head into the drywall--once the collar contacts the drywall skin, the bit cannot proceed any further. These screwdriver bit set made of high-strength S2 alloy steel, these screwdriver bits are very durable. Screwdriver bits has strong magnetism and would attract screws and hold screws firmly. These screwdriver bits designed to have a compact size and a light weight as well, the simple installation can be quickly finished. Built to meet the international standard specification, strictly follow the factory quality control, safe to use.