The apollo ultrasonic tank contents gauge features a tank mounted transmitter as well as a plug-in receiver unit. The receiver features a 200-metre transmitting range, meaning that you can easily monitor the level in your tank from the comfort of your home. The transmitter checks the level in the tank at a high frequency and is simple to retrofit to existing oil and diesel tanks. This gauge is suitable for tanks that are up to 3 meters in height and carries as 12 month warranty.