Aluminium oxide flap discs Grit: P40-P400 Size: 100mm,115mm,125mm,150mm,180mm ... /7.0"X22MM 230MM/9.0"X22MM Applications by different abrasive: 1)Aluminium oxide, (A.O.)Suitable for iron, mid steel ... iron aluminium, non-ferrous metals and wood.2)Silicon carbide (disc in black color ), (C.)Suitable for marbles, stones, building ... not contain metal iron and/or iron compounds. Aluminium Oxide Flap Discs