Recommended for cleaning, opening tight damage and drilling pit caps. Shaft length: 0.750 Shaft diameter: 0.060 Hole size: 0.039 Fits Delta Kits 1/16" collet The Round Tip .039 Carbide Burs are great for drilling the center of the impact point for improved resin flow and to clean out crushed glass or old resin from the pit area. Many technicians prefer round burs because they are easier to control than tapered burs and less likely to skip across the glass