Champion Cutting Tool’s CT7 Carbide Tipped Hole Cutters are the perfect portable tool for the profesional electrician, plumber, mechanic and contractor looking to drill large diameter holes in tough materials using an electric drill. With proper use, the CT7 can be used to drill hundreds of holes, increasing productivity on any job site. The CT7 outperforms bi-metal holesaws. It will cut fast, accurate, bur free holes in steel plate, stainless steel, iron, aluminum, copper, cast iron, fiberglass, and plastics up to 1 inch thick. The ejector spring ejects the slug saving time and the safety collar stop prevents over penetration for safer, faster operation. Full size range includes 9/16 inch to 4-1/2 inch diameter. (9/16″ to 3″ have 3/8″ shank) (3-1/4″ to 4-1/2″ have 1/2″ shank). Also available in sets.