The Yonico 51290 insert cutter spoilboard router bit features a 2-1/2 cutting diameter and a 12mm cutting depth. The bit comes preinstalled with (2) 14mm x 14mm side cutters and (2) 14mm x 14mm top cutters. The overall length is 2-15/16 with a 1/2 shank. Highlights: - Resurface the bed of your CNC machine for a new flat surface - Carbide insert cutters for extended use and affordable tool renewal cost - For CNC machine use only - Solid heavy-duty hardened steel body - Indexable and replaceable cutters for extended tool life - Includes Allen wrench for blade indexing and replacement Insert cutter spoilboard bits feature indexable insert cutters for clean and efficient material removal. Indexable cutters can be rotated when they become dull which extends the life of the bit by 4 times versus standard brazed bits. Rotate the cutters to the next unused edge and you have a brand new bit. Renew your spoilboard surface quickly and efficiently with Yonico insert cutter spoilboard surfacing bit.