This model is designed for four level indication of water level of single tank with audio buzzer at empty and full level of tank. This is used to indicate the water level of the tank and raises a buzzer when the tank is empty as well as full. wireless: no wiring from roof tank to controller unit no external power source is required for transmitters overhead tank transmitter is solar cell powered scale and rust free level sensors. display 4 levels of tank and audio signal whenever a water level in a tank falls below 26% or tank get full