Riding speed reach 4-6km/h the assist power starts automatically. Chinese battery 22.2V 2.0A.Less than 50kg, height 100-160cm. 25.2v0.5A, input 110V-240V (5060HZ). Step on the rear fender physical brake(Restart the motor again if it is stepped on). Color box + pearl cotton. Turn on the "Drip, Drip, Drip" low battery alarm when the remaining. Battery power is about 15%. This item is in the category "Sporting Goods\Cycling\Electric Bicycles". The seller is "iwheels-direct" and is located in this country: US. This item can be shipped to United States.