Line Tracing Robotic Snail Assembly Kit FOLLOWS A PATH - The Line Tracing Snail uses an infrared LED and a photo transistor to detect a black line (magic marker, electrical tape, etc.) drawn on a white background. INCREDIBLE ROBOTICS - To follow a line, the snail emits infrared light from the LED on the underside of its chassis. It uses two small motors and rubber tires to follow the line. A photo transistor picks up the reflection of the infrared light to distinguish black from white surface SEE WHATS INSIDE - The body of the snail is made of transparent plastic to allow viewing of the mechanisms inside. ADJUSTABLE SPEEDS - The snails speed is controlled with a switch: Low-Speed mode is suitable for fine lines and narrow areas where as High-Speed that works best for wide areas and thick lines. SOME ASSISTANCE REQUIRED - To assemble this kit you will need a modeling knife, screwdriver, diagonal cutters, and long nose pliers.