The great innovation with these clever hex keys comes from a spring steel ring on the ball end which grips the head of the screw and gives trouble-free insertion and removal of the screw. The hex key in effect becomes a handle with the screw held securely on its tip. The ball end allows the key to operate at up to 25° from the vertical, very useful in awkward corners, and the keys can be removed from the holder without disturbing the others. The nine piece set covers a size range from 1.5mm to 10mm. Please note that the 3 smallest sizes in the set are standard ball hex keys, not magic keys.