Features:<br />--Can be used with a standard electric drill.<br />--Always use lubrication (water)｣ｬ otherwise the diamond core drill will burn.<br />--Materials and only needs water for lubrication.<br />--This diamond coated core drill bit removes a complete circle from glass｣ｬ marble｣ｬ  tiles｣ｬgranite｣ｬ ceramic or other.<br /><br />Specifications:<br />Size: 6mm/0.23"｣ｬ 8mm/0.31"｣ｬ 10mm/0.39"｣ｬ 12mm/0.47"｣ｬ 15mm/0.59"｣ｬ 16mm/0.62"｣ｬ 18mm/0.7"｣ｬ 20mm/0.79｣ｬ22mm/0.86"｣ｬ30mm/1.18"<br />Material: steel<br /><br />Use note:<br />Start your hole diagonally｣ｬ make a round trace and then hold drill straight.<br /><br />Package includes:<br />3 set Diamond Hole saw(30pcs)<br />