The tank-like molded casing and a rugged internal gear mechanism are built for the harshest student environment. Runs on four “C” batteries and has variable speed adjustment knob. External power input accepts phone plug cable (included) to power the car with a DC power supply or 850 Universal Interface signal generator.https://www.pasco.com/products/lab-apparatus/mechanics/carts-and-tracks/me-9781#specs-panel