1. Thin knife,thickness less than lmm,smooth edge of the corrugated paper after cutting little crushing,high quality paper board. 2. A pair of emery wheels for each knife. 3. 2 kinds of sharpening devices-manual and pneumatic,sharpening time and intervals decided by customers.By manual operation sharpness and longer life of the knife and the wheel is available. 4.Stability and long duration by gear or rack drive.