The Crawler also provides a four-wheel independent bumper, which is placed between the body and the tire as a buffer device, mainly to absorb the vibration generated by the vehicle when rolling over the potholed road surface, to support the car body, and in the coordination of bumper, it makes the control more stable. In addition, in order to be able to drive on all lands, the Crawler is equipped with a large sized high-elastic rubber tires. Each wheel is 105mm in size. The controller of four-wheel-drive vehicle can call on sensors in mobile devices, such as TIME, GPS, gyroscope and MIC, etc., which makes its playing methods more diversified.