Master Mechanic, 1/2" x 3-1/4", Glass & Tile Carbide Tipped Drill Bit, Spear Pointed Tip Reduces Breakouts When Drilling From 1 Side To The Other, May Be Used With Any 3/8" Drill Press Or Variable Speed Drill, Zinc Finish, Recommended For Use In Ceramic Tile, Mirrors Or Glass Of All Types, Marble, Tile, Vitrolite & China, Carded.