An earlier version of this item: https://sphero.com/collections/mini
Still compatible with their app etc., but unfortunately the integrated rechargeable battery seems to have gone bad. Changing the battery is not easy, and requires cutting the device open with a saw, so if you're not happy doing that it's not likely to be useful to you.
Sphero 2.0, needs battery replacement (Bernards Heath AL1)
This offer has been gifted to someone and is no longer available.