Description: Quickly repairs damaged bolts and tighten the nuts in place. Features: Allows you easily fix the ends of broken or rusted bolts to easily reattach a nut. It is a drill bit attachment, simply attach it to the end of your power drill (can be attached to any drill) to repair damaged bolt ends. Simple operation, using the lowest speed on the drill bit, and then slightly applying pressure to remove the burr. It works on pretty much any kind of bolt no matter what it's made from, including stainless steel, hardened steel, mild steel, copper, brass, aluminum, fiberglass, wood, and plastic. Though, it is ineffective on Chrome-Moly (chromium and molybdenum). The deburring drill bit attachment tool is best used on your drills low speed (50-400 RPMs) since using it on a higher speed with shortening the life of the tool. To use it properly, the tool should not chatter, it should not overheat the workpiece, it should not spark, the threads should be sheared off, not folded over, and you should only be used to remove the damaged threads, not make the end of the bolt into a pencil. Specification: Material: alloy Colour: silver Length: 48mm Fits Size: 8-32 bolts (.164) up to 3/4 (.750) -10 inches (4 mm-19 mm). 4 Pack Contents: 4 Pieces Tools 8 Pack Contents: 8 Pieces Tools