The Apollo Ultrasonic is a two-part level measurement device, consisting of a transmitter (measuring device) and a receiver (display). The level measurement device measures the distance to the current fill level in the tank using ultrasound and transmits the data via radio transmission to the display device. The receiver is plugged into a well-visible free socket (230 V/AC). The display device permanently shows the current tank content in a 10-step bar chart and blinks when the alarm level is reached. The device is used for monitoring tanks containing heating oil, diesel, and other liquid media such as lubricating oils, biodiesel, waste oil, cleaning agents, Ad Blue, and water.