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 it 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.