Anytime Tools 5 pc DIAMOND DRILL BIT SET for GLASS ROCK STONE TILE Wire Gauge #36 - #60 Drill glass, marble, masonry, rocks, concrete etc... Super duty diamond coating on nickel plated high speed steel will give you excellent results even in semi-precious stones. Numbered sizes: #36 (0.1065"), #50 (0.0700"), #54 (0.0550"), #56 (0.0465"), and #60 (0.0400") Note: use on a low speed with coolant (water/oil)