Gear ratio: 4:1, roller width: 110 mm (4.33 inch), roller diameter: 55 mm (2.17 inch), maximum opening: 0-5 mm (0-0.2 inch), flat area (+/- 0.01 mm): 57 mm (2.24 inch).
4:1 reduction gear ratio allows the rollers to make one complete turn for every four turns of the mill rolling handle. It relieves the amount of force needed to operate the rolling mill.