Liquid flow sensor Flowmeter 0.3 to 6 liters/min Water flow sensor. Flowmeter which detects the flow of liquids from 0.3 liter per minute to 6 liters per minute.Internally it has a Hall effect sensor detecting the magnetic field provoked by the motion of the blades that is generated with the passage of liquid.Delivers square pulse output signal whose frequency corresponds to the liquid flow. Robust mechanical design， encapsulated weatherproof. Easy to use.