LMT Onsrud - 91-104 2 1/2" Surface Insert Planing Router BitDesigned for surfacing MDF, particleboard and balsa core where "flow through" or "high flow" fixturing is employed using large capacity vacuum pumps. This method of surfacing spoilboards allows for much faster table planing. Cutter body, use 91 125 blades Cut Diameter: 2 1 2" Shank: 1 2" Cut Length: 1 2" Overall Length: 2. 800" Flute Type: Surfacing