Bike" is a way of travel, not to buy oil, power from the two leg spin two wheels allows travel destination. Just use the power from the two legs. It doesn"t pollute, reduce carbon dioxide emissions and save cost. And increase the quality of life for the citizens, therefore, we should reduce the hot city with our hands by reducing the use of energy, reduce greenhouse gas emissions. As well as to increase the green area. To increase the source of carbon dioxide removal in the city.