Description:Three color LED indicate low (red), medium (yellow),high (green) water, low water pumping or high-water pumpingcan be switched on and off when you press the function switch bounce(ie not pressed) when low water relay (external pumps work),start adding water, the water level rises to a high level relay off (pump stopped working)until the water level drops below the low water level again relay again, the above process cycle.This feature is used in automatic water equipment,allowing the water level is maintained at a low level and high level between.When the function switch when pressed, when the high-water relay (external solenoid valve),begins to drain, the water level drops below the low water relay off (solenoid valves stop working)until the water level rises again to the high-water relay pull again, the above process cycle.This feature is used in automatic drainage device,allowing the water level is maintained between low water and high water level.Specifications:controller size:42*69mmsensor size:83*21mmPackage includes:1 x Liquid Level Controller Module Water Level Detection SensorNote:1.Dueto different producing batches, product details might be a little different. If you minding the difference, please buy it carefully.2.Please allow 1-3mm differs due to manual measurement.3.Itemcolor displayed in photos may be showing slightly different on your computer monitor since monitors are not calibrated same