48V 250W Rear Cassette motor Rated Voltage(V):48 Rated Power(W):250W Wheel Size (inch):16”20”24”26”27.5”28”29”700C RPM:207-270 Rated Speed(km/h):25-28 Rated Efficiency(%):>=80 Reduction Ratio:1:4.5 Weight(KG):2.6 Open Size(mm):142/142 Drive and Freewheel:N/6-9S/7S-11S Spokes Specification:12G/13G BUILT-IN BATTERY BUILT-IN MANUAL MODE, ASSIST ANCE MODE AND ELECTRIC MODE SWITCH AND USE EACH OTHER MAKINGIT EASY TO COPE WITH DIFFERENT CYCLING ENVIRONMENTS.