... preparation such as deburring, polishing, and removing scale, rust, corrosion. twist knot cup brush,Heavy-duty cleaning of large metal surfaces ... .35 and 0.50mmRPM:12,500Steel wire type:brass-plated steel wire,phosphated steel wire,galvanized steel wire and steel cordBowl type:galvanized bowl ... ,85,90,100 and 125mm 4" cup brush with crimped wire