Moko has a new video showing the W2 wearable beacon being placed in water:
The W2 advertises iBeacon, Eddystone and acceleration. It’s rechargeable via USB and can be configured to provide continuous, button triggered or motion triggered advertising.
The acceleration sensor is the STMicroelectronics LIS3DH that’s configurable for scales of up to ±2g/±4g/±8g/±16g.