Semiflex Sanding Discs Dimension(mm) Grit Available Abrasive Available Backing Available 100x16 60 - 180 A, C Red fibre and plastic 115x22 60 - 180 A, C Red fibre and plastic 125x22 60 - 180 A, C Red fibre and plastic 180x22 60 - 180 A, C Red fibre and plastic 230x22 60 - 180 A, C Red fibre and plastic Applications by different abrasive: 1) Aluminium oxide, symbol: A Suitable for iron, mid steel, welding rods, cost iron aluminium, non-ferrous metals and wood. 2) Silicon carbide (disc in black color ), symbol: CSuitable for marbles, stones, building materials, hand materials, glass.