Large Silicone Polishing Wheels, Light Blue, Fine Grit, 4 Inches By 1/2 Inch | POL-490.70 Great for polishing and use with buffing machines Made of silicon rubber with impregnated silicone carbide Fine grit wheel 4 inches by 9/16 inch with a 1/2 inch hole Use with a 1/2 inch straight arbor only; maximum 3,600 RPM