1、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 2、Can be used with a standard electric drill( Excluding in this item ) 3、Easy to use, high quality,good performance, long life 4、Excellent for making clean and accurate hole on glass , tile and marble 5、Always use lubrication (water ), otherwise the diamond core drill will burn Features: - This is a brand new item - 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 - Can be used with a standard electric drill( Excluding in this item ) - Easy to use, high quality,good performance, long life - Excellent for making clean and accurate hole on glass , tile and marble - Always use lubrication (water ), otherwise the diamond core drill will burn - Start your hole diagonally, make a round trace and then hold drill straight - Size: 1 1/2 inch (38mm) &1 3/4 inch (45mm) Package Included: 2pcs Diamond Coated Hole Saw Drill Bits (38mm & 45mm)