You forget to turn off the tap, the washing machine and the water level in your aquarium falls, the water tank is empty or suddenly overflowing, there is water in your basement etc. These things happen, and when they do, they often cause a lot of trouble and a lot of damage. Prevention is still better than cure and this kit comes in. This multifunctional device is easy to operate in a variety of applications: 1) LED control of the set liquid level: Low, center, high; 2) Controller: The relay automatically switches a pump and/or valve to keep the liquid level between the low and high notes; 3) Alarm: If the sensor detects a level that is too high or too low (selectable), the relay operates a bell or other alarm device.This text is machine translated.