This 1/4" hex holder has a strong Neodym magnet to retain your screwdriver bit. The 1/4" hexagonal shank is chrome-vanadium steel. The unique MagicFlip features a robust steel sliding outer sleeve. A Neodym ring magnet on the end of the sleeve securely holds the screw head on the tip of the screwdriver bit. With the ring magnet taking a firm hold, even on long or large screws, starting and driving the screw is far easier. As soon as the outer ring comes into contact with the work surface it retracts, leaving the screw head visible. This allows precise depth control for neat and consistent countersinking. The MagicFlip is also suitable for drywall screws.