1. Using high-quality materials, the quality is guaranteed. 2. Ultrasonic distance measurement and obstacle avoidance, automatically rotate or back to avoid obstacles when encountering obstacles. 3. The digital tube displays the current obstacle distance in real time, up to 5 meters. 4. Introduce a new simulation design concept to make the circuit board more like a car chassis, a dedicated motor drive chip, control the forward and reverse rotation of the motor, and flexibly control the car's forward, backward, in- rotation and other actions; the STC single-chip control system is closer to the people. 5. A wide range of applications, training hands-on ability. Working voltage:5V Power supply mode:4 x AAA batteries (not included in the delivery) Working current:no-load less than 300mA (the motors are working but not walking) The universal wheel version reduces the walking resistance of the car, saves power and lasts longer If you purchase loose parts, you need a certain welding foundation and patience, and you need to bring your own welding tools. Attention: 1. This product is a DIY kit and not the final product. 2. This welding project requires basic electronic knowledge and hands-on skills. 3. The delivery is in loose parts, which need to be welded and assembled by yourself. Some accessories are sent randomly and cannot be specified, which will not affect the use. Colour:As Shown Material:Plastic Package Contents: 1 * DIY trolley welding kit Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.