To be used only on CNC machines and routers with automatic feeding. Using the highest quality sub-micrograin carbide These bits have a special proprietary edge processing system featuring a super high polished cutting edge with a unique “mirror finish” Resulting In clean cuts, less chance for chip re-welding, a superior surface finish and a longer tool life. Right hand helix right hand cut, #57307, direction: down-cut, (D) diameter: 3mm, (B) Cutting height: 12mm, (D) shank: 6mm, Overall Length (L): 50mm, flutes: 1, 57307 Solid Carbide CNC spiral 'o' Flute, aluminum Cutting 3 dia x 12 x 6 shank x 50mm long down-cut router bit