Features: Product function: Check whether there is-liquid flow in the pipeline: 40-150mVMIN. Product features: small volume/high flow accuracy Photoelectric principle: more hygienic and safe. Working principle: The-pulse signal generated by the impeller cutting light-path flowmeter without-magnet and pure optical induction can be used to measure the water flow by calculating the rotation-time of the impeller which is-more suitable for long-term measurement of drinking water. Application: Water dispenser/water-heater/coffee machine/small flow control application. Applicable scenario: Measure the water flow and output pulse signals. Specifications: Material:Plastic Size:As Picture Shown Package Includes: 1x Water Flow Sensor note: ①Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. ②Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thanks for your understandings.