Insert carbide spoilboard Surfacing & Rabbeting router bit great for cutting large surface areas and surface planing, also suitable for router sled machines, make sure that your router sled is fully stable and squared.#Rc-2257, (D) diameter: 2-1/2, (B) Cutting height: 1/2, (D) shank: 1/2, overall length (L): 2-1/2, Max RPM: 19, 000, replacement knives: hma-12 (2), RC-2257 CNC insert carbide spoilboard Surfacing, Rabbeting, flycutter, slab leveler & surface planer 2-1/2 dia x 1/2 x 1/2 inch shank router bit