The Mopeka PRO sensor combines the best technology of ultrasonic sensors and offers improved sensor performance. LPG tanks/ cylinders: All steel LPG tanks and gas cylinders up to 3,785 litres / 1,000 gallons, horizontal or vertical cylinders. Mounting: Attaches with magnets to the bottom of the steel gas cylinder. Reading the fill level via Bluetooth: Free Mopeka Check APP on your smartphone or tablet; or Mopeka Check LED display. Also compatible with: The Mopeka Wifi Bridge, which allows remote reading of the sensor via the APP. Power supply: CR2032 battery