Design Their simple design and compact size make it easy to carry the tool in your tool bag. Quickly slip it into your hand drill and start repairing parts. The operation is simple: use the lowest speed on the bit, then apply light pressure to remove the burr. Effective on stainless steel, hardened steel, mild steel, copper, brass, aluminum, fiberglass, wood, plastic. Fits size: 8-32 bolts (.164) up to 3/4 ″ -10 (.750) - (4mm -19mm). Quickly secure the bolts and tighten the nuts in place. Simplifies the repair process, eliminates the need to replace expensive or hard-to-find hardware. Simple to use, using minimum drill speed, then lightly applying pressure to remove burr. Effective on stainless steel, hardened steel, soft steel, copper, brass, aluminum, fiberglass, wood, plastic. High strength and hardness. Features: Material: stainless steel. Color: silver, black. Product dimensions: 2.2 x 2.5 cm. Fits sizes: 8-32 bolts (.164) up to 3/4 & Prime; -10 (.750) - (4mm-19mm) Proper Use: This tool works by shearing metal layer by layer. Slow speed, with no unnecessary cutting and the use of cutting oil or other lubricant will give it a long service life. Contents: 1 external chamfer tool.