This is a great item keep in the tool kit. Especially if you are doing any work in metal panels or steel studs and you have to make your own knock-outs. This will quickly and easily clean up the edges to save wear and tear on your wires, gloves and most importantly your fingers and hands. Cleans burrs from both sides of the hole in seconds, saving time and labor. Removes burrs from up to 10 gauge mild and stainless steel, copper, brass, aluminum. Will fit in almost every drill, minimum chuck size 3/8" Cutter size - 13/16" diameter. Simple Bi-Directional Operation - run tool clockwise to deburr, counterclockwise to clear chips