The frame design of the Motan M-5500 electric bike is to commemorate the Flying tigers,that the United States volunteers together to Aidhua Air Force in the second world war.The shark mouth logo on the frame is the symbol of the Flying Tigers.The Motan M-5500 is designed with a strong farme that can carry a load of 350 lb easily.Durable and stiff 6061 aluminum alloy frame with the fat tires,make this bike especially perfect for mountain,wasteland,also effective on the road,trail,city,beach or the snow,etc.