Magna Extra Hard bits are suitable for soft fixing. Ie. screwing into wood and high wear applications. Screwdriver bits are typically made up of a shaft and a tip. A screwdriver bit's shaft is typically hexagonal in shape, with six flat sides. This shaft is fitted into the end of a screwdriver that has a bit holder. The shaft's shape prevents the bit from rotating within the bit holder. The tip end of a screwdriver bit may have many shapes.The bit's head is designed to fit into the head of a screw. As the screwdriver is spun, the bit rotates as well. This is what causes the screw to turn. Head style: Pozi Length:  89mm With four more contact points, the Pozidrive screwdriver is an enhanced version of the Phillips screwdriver. These points reduce the likelihood that the bit will cam out, enabling more torque to be applied. Additionally, this shape offers a larger driving surface and reduces wear.