20 Mixed Vacuum Brazed Grit 46 Diamond Engraving Burs For Granite and Concrete 20 pieces Mixed Set Vacuum Brazed Diamond Engraving Points Diamond Grit 46 (Coarse) 6mm (1/4") Shank Head Types: Sphere, cylinder, bullet, needle, taper, round corner, groove, cone, etc.. For granite, marble, glass, composites, concrete, softstone, terrazzo, gemstone, ceramics, porcelain