Morse, MHSG28 (216289), 1-3/4" (44mm) diameter, carbide grit edge hole saw is designed for use on hard or abrasive materials, like cinder block, cast iron, unglazed ceramics, fiberglass and composites. Gulleted cutting edge allows for chip clearance, while cutting. Unique side slot increases leaverage access various thicknesses of materials, easing slug removal. One (1) hole saw per box. Seperate arbor required, use Morse MA35PSNCT (139830) or MA45PSNCT (139847)