This G1/4" Flow Sensor includes a durable plastic valve body, an inner rotor, and a hall-effect sensor. Flowing water causes the rotor to spin, and its speed varies depending on the flow rate. The hall-effect sensor detects these changes and produces a corresponding pulse signal. This flow sensor is perfect for use in water dispensers and coffee makers. Our selection of water sensors features a range of diameters, so you're sure to find the right fit for your needs.