Swiss Made. Silicon carbide abrasive in a specially formulated rubberized bond that breaks down more slowly and lasts much longer than silicone-bonded abrasives. Produce a superior finish. Use the Brown Prepolishers to remove light scratches and prepare surfaces for final polishing, then use the Green Polishers to impart a bright high shine. Mounted shapes have 3/32shanks. Unmounted shapes have 1/16arbor holes and can be mounted on our Screw Mandrels. Max. operating speeds: 20,000rpm for brown and 10,000rpm for green.