The Faithfull Magnetic Bit Holder, Finder & Guide is designed for use with standard 1/4 Hex shank screwdriver bits and can be used with any variable speed drill or cordless screwdriver. The outer sleeve or finder slides over the screw head and helps keep the bit in place. This is especially useful when driving or removing slotted screws. The combination of both the outer finder and a magnet holds the screw firmly in position making for easy starting. The extra length bit and finder also extend the reach of a driver drill for hard to reach places. Extendable from 76-115mm. Ref: UTTK1665