The all new from the ground up, Traxxas EZ-Start™ System brings the power and convenience of push-button electric starting to the TRX 2.5 or 2.5R Racing Engines. Simply plug in the hand-held control unit, push the button, and the EZ-Start System automatically heats the glow plug and the lightweight, compact on-board drive spins the engine. Traxxas' exclusive Smart Start™ technology monitors critical starting functions, automatically sensing and diagnosing potential problems for trouble-free engine starting every time. The EZ-Start requires a fully-charged, 7.2-volt, 6-cell battery pack and a charger (not included). A single charge should provide a full day of starting.