Box-shaped beacons can be cumbersome to wear. Instead there’s a range of beacons in a watch style.
The iB001W is rechargeable via USB.
The H1 is rechargeable and also has an accelerometer that can be used for motion triggered broadcast to save battery power.
The B10 is different because it has an SOS button. It also contains an accelerometer for extra interaction possibilities.
The ABN05 is one of the smallest and measures only 23.9mm x 23.1mm.