The Cabelet Bracelet is a product that you probably already have in some form, a mobile battery. If you use your phone a lot, then you might find yourself needing some juice while on the road. The Cabelet Bracelet is that mobile battery, in a smaller form.
It comes in orange and bronze, brown and bronze, white and silver, or black and silver. They come in small, medium, and large which is essentially a size somewhere in between 5 to 8 inches.
So I will stand by my comment that this Cabelet Charging Bracelet is a smartwatch accessory. It could be probably worn on the same hand with your smartwatch, or on the opposite wrist. Heck, if they are on the same wrist, you could probably charge a smartwatch with the Cabelet Charging Bracelet.
You should be able to get the Cabelet Charging Bracelet for about $24, and it is normally priced at $69.99 on the Kyte and Key website, for those that need a Micro USB or Lighting Pin connector.