and high quality.This diamond coated core drill bit removes a complete circle from glass, tiles, marble, granite, ceramic or other.Materials and only needs water for lubrication.Always use lubrication (water), otherwise the diamond core drill will burn.Works better with a electric drillStart your hole diagonally, make a round trace and then hold drill straight.Model: 20 Pcs 3-50mmColor: SilverSize:3/4/5/6/8/10/12/14/16/18/20/22/25/26/28/30/32/35/38/50mm012/016/020/024/031/039/047/055/063/071/078/087/098/102/110/118/126/138/150/197 inchQuantity: 20 pcsPackaged included:20pcs Diamond Coated Hole Saw Drill BitsOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.