This flush trim router bit was designed to eject chips down for clean cuts in aluminum and ACM materials. Perfect for routing aluminum using a template. Features a special carbide grade to perform high-quality cuts in aluminum.#51522, Direction down-cut, diameter (D) 1/4, cutting height (B) 1/2, shank (D) 1/4, overall length (L) 2-1/2, Type down-cut, replacement bearing 47723 (2), flutes 2, 51522 Solid Carbide aluminum Cutting flush trim spiral down-cut 1/4 dia x 1/2 x 1/4 inch shank