... edges holdout, durableSuitable for form grinding, knives, Measuring instrumentGreen silicon carbideGCgreenOnly no harder than Boron carbideSuitable for grinding Hard alloy, Optical glass, vitrify ... two sides wheeltype 8 taper cup wheel, type 9 dish wheel)Material(A,WA,GC,C,DA,DC,PA,38A) PA Parallel Grinding Wheel