stone cutting disc high quality reasonable price, best services stone cutting discFeatures:1) ... cutting wheels for steel or stone2) Size: 4", 4-1/2", 5", 7", 9", 12", 14" and 16"Material (the reinforced ... disc2) A30: aluminium oxide material grit 303) R: hardness grade4) 5: structure number5) B: combined material "resin"6) F: fiber glass ... p.m, means meter per second, rotary speed stone cutting disc