It combines filigree appearance, light weight (only 433g in comparison the DH-3N80 weighs 490g) and extremely smooth rotation (40% smoother than DH-3N80) in proven Shimano quality. Furthermore the dynamo has a center lock brake disc mount. So the DH-S701 is the perfect choice to combine efficient power generation, comfort and safety. The overvoltage protector helps not to blow up any light bulbs and guarantees a safe and bright way.