RE: What is the definition of a roller?
i think everyone is thinking about this too literally, its like saying "ready to run" means you pull the car out of the box, flip the switch and drive. sometimes you have to buy the batteries or fuel, charge the battery, sometimes even paint the body or glue the tires.
and shouldn't a "kit" come with EVERYTHING to build your car? servo, esc, battery, reciver, controller, paint for the body, glue for the tires, whats a kit if it doesn't come with everything to make it? the exception is the "chassis kit" so you know its only for the chassis.