Master Mechanic, 3/8" x 3-1/4", glass & tile, carbide tipped drill bit, standard shank, 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.