Features and Benefits: (3) 3/8 " cutters. Arbor assembly (11122) with standard pilot, and an extra pilot. Cutters fit 3/8" and 1/2" hand held drill chucks. Patented tooth geometry also prevents chip clogging when cutting steel, sheet metal, plastic and wood. Made of High speed steel. These annular tools cut clean, burr-free and round holes fast unlike twist drills that push or hole saws that tear through materials. There's no dead zone, so less thrust is required and no deforming of stock or jagged edges occurs. The cutters are for the heavy-duty use in sheet metal and materials up to 1/2" thick. Multiple cutting teeth, precision ground which allows for a long tool life. These cutters are packaged in a plastic carrying case.