grinding wheel recessed one side contain(white,brown,pink)aluminum oxide,silicon carbide,zirconia oxide, ... Germany to make high quality coated abrasives. Grinding wheel recessed one sidediameterthicknessholeconcave diameterconcave depth2003275125164020300401272001350203504013633040050203265205006320753053752575301001506007530525100150250 grinding wheel recessed one side-HN