Material: Diamond & Iron Matrix Color: Silver Surface Treatment: Electroplating Drilling Diameter: 40MM / 1.57Inches Model: YJ9323 Application: Glass Deep-processing Scope of application: glass Marble / Tile / Granite / Jade, etc. Features:- 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.- Use lubrication (water), otherwise the diamond core drill will burn.- Start your hole diagonally, make a round trace and then hold drill straight.