Water flow sensor is mainly consists of plastic valve body, rotor assembly and Hall Current Sensor.It is installed in the hot water inlet end for detecting water flow. When water through the flow rotor assembly, Magnetic rotor will rotate and Speed will change as the flow change. Hall Current sensor output corresponding pulse Signal and feedback to controller, then the controller will control the flow. Can use for Water heaters, credit card machines, water vending machine, flow measurement device. Specification: The lowest rated working voltage: DC4.5 5V-24V. Maximum operating current: 15 mA (DC 5V). Working voltage range: DC 5~18 v. Load capacity: 10 mA (DC 5V). Work temperature: 80 Work humidity range: 35%~90%RH (no frost) Allowing pressure: pressure 1.75Mpa Storage temperature: -25~+80 c Save humidity: 25%95%RH Flow Range :1-30L / min External threads: 1/2" Size: Approx.54*27mm/ 2.13 x 1.06inch Package Includes: 1 x Water flow sensor