This easy to use line tracer comes the electronic components already assembled. Using optical sensors to detect a line drawn on the floor, this line tracer robot runs along the line using control motors. If the left side is brighter, the left motor rotates, and the right motor stops. It makes Chokomacar turn right, ad as a result, the traveling direction of Chokomacar is shifted along the line.Using your own soda bottle and and a little imagination, you can customize the look to create your own unique vehicle design. Requires 1 AA battery (not included).