There are 3 batteries involved.
One set of batteries is used in the controller. This is a typical battery that can be purchased at virtually any store.
There is a watch battery that makes the watch function like normal. A jeweler can change this battery, or you may be able to change it yourself.
The gimmick's battery is rechargeable with a usb connection.
Answered at 12:00pm on January 2nd, 2019 by joshburch (215 karma)