... )Different types and sizes 3)Shank dia:3mm,6mm Diamond engraving burrs (1)used for foundry grinding, grinding disc, oil ... Application: metals grinding, mend etc.(4)Diameter of shank:Φ3mm,Φ6mm(5)Material: diamond, PA, (pink fused alumina)WA(white fused alumina ... ), A(alumina),GC(green silico carbide) More product pcs: diamond engraving ...