?TIPS ?This product is for educational purpose in schools and other pedagogical contexts. Please use under adult supervision. Sonar:bit module: This module is installed in the back to make sure it goes freely avoiding any obstacle.It is a 3-wire ultrasonic module with the working voltage between 3-5V. It is available to be used to 3.3V or 5V micro-controller system. With only one 3-wire(GVS) cable, it can work properly. Compared to the normal 4-wire ultrasonic module, it has saved one IO port. The measurement range of sonar:bit is 4cm-400cm. It can output stable and accurate measurement data with ±1cm tolerance only. Light-bar module: It can brings you mutiple color with simple assemblling methods.It comes with 8 Rainbow full color LEDs. You can update it to a car with auto-headlights and rainbow lights. Line following module:Equipped with double infrared probes, it can detect the distance between 2~12mm accurately that can achieve the function of line following around the circles, the detection of the black lines and the detection of the edge. The Ring:bit car line following module, light-bar module and Sonar:bit are dedicated modules designed for the Ring:bit car.