You want a rotostarter, starter boxes are bulky and dont fit in your back pocket like a rotostart.

I got mine from this guy on ebay [link=http://cgi.ebay.com/Power-Battery-Starter-for-RC-Cars-Trucks-4X4-COMPLETE_W0QQitemZ170090342916QQihZ007QQcategoryZ3 4063QQcmdZViewItem]click here[/link]

Thats a complete kit with backplate that replaces the pullstart and a 7.2volt battery and charger... if you already have a 7.2 volt charger and battery check his store as he sells just the starter and backplate only also.

I am still waiting for my stuff to arrive form him but he has cutthroat prices and excellent service.