Black (Low Density): Used to remove light coatings and clean. Suitable for stainless steel, low carbon steel, aluminum, plastic, cement, wood, and stone surfaces.
Blue (Medium Density): Hardness between purple and black wheels. Used to remove rust, polish corrosive surfaces, and clean concrete. Ideal for shipbuilding, bridge industries, and more.
Purple (High Density): Used to clean welding slag, deburr metals and woods, remove severe rust, and polish heavily corroded surfaces.