Electroplated diamond coated hole saw. The diamond coated cutting edge allows precise chip-free cutting of glass, granite, marble, porcelain and ceramics. With an integrated water-cooling sponge that prolongs the life of the cutting edge by reducing heat build-up. Sponge must be soaked in water before use. 20mm and 45mm cutting depth makes this range ideal for plumbing and electrical installations. Rounded 10mm hex shank means it will fit both handheld or pillar drill chucks.