Cobalt Spotweld Cutter Kit cuts faster and lasts much longer that HSS cutters. Made from superalloy cobalt Steel, the tips are self centering and safe for pneumatic drill use and designed to cut up to 5x faster than standard cutters. Kit includes one each of the following cutters 1/4", 5/16", 3/8", and 1/2" in a cherry wood box with space for the 50193 Cobalt Stepped Drill Bit. Not for use on newer cars with Boron Steel or other high strength steel. Limited lifetime manufacturer's warranty. MADE IN USA.