Amazon.com: DooQi CADA Technik Power Function Kit for Technical Cars, Including 3 Motors, LEDs, Battery Box and 2.4 Ghz Remote Control (Compatible with Many Models Such As CADA) : Toys & Games
LEGO® Technic™ Small Hub Battery 45612 | LEGO® Education | Buy online at the Official LEGO® Shop US
LEGO LEGO Functions: Power Functions AAA Battery Box (88000) for sale online | eBay
LEGO has a mysterious new rechargeable battery, what can be the product? - RacingBrick