Bondhus balldrivers are constructed of maximum strength Protanium® high torque steel, which is up to 20% stronger than Carbon Steel, 8650 or Chrome Vanadium. Gives you all the power you need to tackle even the toughest jobs! ProGuard Dry Surface Technology: prevents rust 5x better than other leading brands, and protects the tool. Sizes are engraved on each tool. Inch sizes come in BriteGuard Finish. Metric sizes come in GoldGuard Finish. Comes with the Bondhus® lifetime warranty.