Pozidriv®-alternative bits have an eight-bar pattern as opposed to Phillips bits which have a four-bar pattern. The extra bars provide greater torque with less cam-out. They are for use with Pozidriv®-alternative screws. Power bits are ideal for use with power drivers. Insert bits are for hand drivers, or may be used in power drivers in conjunction with a properly fitting bit holder. Extra hard bits are used specifically for use with case hardened screws.