This one tool will cut holes from 2in. to 12in. diameter in steel (up to 20 gauge) or wood (up to 1in. thick) using your power drill. Great for cutting speaker holes, gear shift holes, radius cut corners, and more. After setting the circle diameter, drill a center hole, insert the pivot pin, attach your drill to the special triple flute cutting bit, and you're off. Sturdy aluminum body and long-lasting cutter bit will give you long service. NOT FOR USE ON STAINLESS STEEL.