Dremel 9935 Structured Tooth Cutter Bit
Structured tooth tungsten carbide cutter, 1/8-inch shank, 5/16-inch diameter ball shape cutter.  If you have a lot of material to remove the fast cutting, sharp teeth will work wonders.  Can be used on a variety of material including fiberglass, wood, plastic, epoxy, rubber, laminates, particle board, soft metal, and ceramic tile.