Fiberglass-impregnated materials are well known for their abrasiveness along with a tendency to Fray or shred during machining along with heat created by the router bit. Amana Tool response to these challenges is an extremely free-cutting, multi-edged glass reinforced plastic (GRP) multi-flute tool that shears the material without shredding or imparting unnecessary heat.#51535, Direction down-cut, (D) diameter 1/4, (b) Cutting height 3/4, (D) shank 1/4, overall length (L) 2-1/4, flutes 4, 51535 Solid Carbide CNC spiral for glass reinforced plastic cutting 1/4 dia x 3/4 x 1/4 shank down-cut ZRN coated router bit