The most popular physics laboratory 'toy' on the market! Used in PTRA and MODELING workshops. This flip over buggy runs with constant speed and glowing headlights and blinking taillight. Vary friction with removeable tire tread. Requires two "C" batteries (not included) to run at full speed. Use a conducting slug (as simple as foil-wrapped cardboard!) in place of one of the batteries and run the buggy at half speed...with half-speed blinking lights. Combine with our M-26 Stopwatch for data collection. Body construction is plastic. Length: 17 cm.