3M Roloc Bristle Disc Safer, faster and cleaner than wire brushes Ideal cleaning disc for machining aluminum Excellent also for removing old seals on oil pans, valve covers Optimum number of revolutions 12,000 - 15,000 rpm, maximum revolutions 18,000 rpm Processing equipment: angle grinder in conjunction with a Roloc backing pad P36, very coarse, purple Diameter: 50 mm