The Rokenbok Control Pad simultaneously controls 8 Rokenbok RC vehicles. You can use 4 Control Pads at the same time as they all plug in to the front of the Radio Control Center that comes in the Start Set. Every Control Pad can control every Rokenbok RC Vehicle. You simply match the Radio Key number of the vehicle by selecting that number on your Control Pad. Control Pads do not require any batteries. Requires Start Set.