Reads the oil level and sends the reading to an indoor receiver. Suitable for use with heating oil and diesel. Fits plastic tanks up to 3m deep. Easy to retrofit. The transmitter needs a 20mm or 32mm hole on top of the tank. No power required at the gauge, has a long-life lithium battery. Comes with an electronic receiver that plugs into a 230V socket. Receiver can be up to 200m away from the tank. Tank level is displayed in ten graduations.