Made with Bosch Carbide Technology, each tooth is an optimum grade of the hardest metal, laser-welded and ground 6 times for the perfect cutting shape. Lasts up to 50x longer than bi-metal hole saws in tough materials. Designed for tough jobs and all-round trades work. For use with the Bosch Power Change Plus keyless arbor with 105mm pilot drill bit. Replacement pilot drill bit (Code 139PF) for use with brick and soft tiles. (Code 155PF) for use with wood, drywall, plastics and metal.