From the Manufacturer
Double your time to play with Inu. As one of your batteries may need to charge you can always have a back up. Never be without your new friend, Little Inu. Replacement Battery Pack 2x the storage for longer play. Double your Play Time. NiMH 7.2V 1500mAh rechargeable battery. Never be without your new favorite friend. With Inu it is always an adventure.