This is the RDLogics Starter Box II for the Traxxas Revo 2.5 and 3.3 trucks. This features a new, wider belt design for longer life and more torque to start your engine. This runs off two 7.2V stick packs, or a 12V battery or power source. Batteries are not included, but are available in our eBay store. Your truck must have a flywheel large enough for use with a starter box. If you need a flywheel, get the Traxxas TRA4142X from our eBay store.