Ultrasonic Portable Wind SensorBy connecting the BLE wind sensor, you can get instant apparent & true wind readings Bluetooth, solar powered and IPX8 pocket sized ULTRASONIC anemometer. This self powered Bluetooth 4. 1 ULTRASONIC windmeter can work for 29 days without charging while measuring, and an entire year in sleep mode thanks to its solar panel. Built with ULTRASONIC sensors, it will provide you with one of the greatest accuracies we have ever achieved in an anemometer.