RockHard Bi-Metal Hole Saws feature shredding rip guard teeth, built with more steel and cut & sharpened to the finest edge for added strength. These teeth provide incredible cutting efficiency and offer increased productivity on any job, as well as better hole quality. Each bi-metal saw is coated with a low friction, thermoset paint coating. Each also is made from M3 high-speed steel and fortified by cobalt. RockHard hole saws are premium quality, affordable, and long-lasting to provide professionals strong endurance and exceptional results.