Bulk Packaged 6pc Coarse 1/4 x 1/2 inch Sanding bands. Use with 1/4 x 1/2 inch Sanding Mandrel, not included. Compare to Dremel 431. For use with Dremel Type Rotary Tools. 35,000 RPM is recommended for brass, steel and aluminum. 10-35,000 RMP is suggested for ceramic, hard or soft wood, stone and shell. The RMPs recommended for plastic are 10-20,000; for copper 25-35,000.