The General Tools #4 Circle Cutter 4 Inch Max is perfect for making precision circles in a variety of materials, from sheet metal, to brass, copper, soft steel, wood, and more. Its durable body of heat-treated tool steel is adjustable to various diameters with the included hex wrench. And with a maximum RPM of 500, it is safe to use with any drill press. Includes a #4/5 Blade and a #5/6/55 Drill (1/4 in. pilot drill bit) and hex wrench.