DN20 pipe 3/4'' water flow hall sensor Hall Flowmeter , flow meter Control Water 1 60L/min tools|Flow Meters| - AliExpress
Turbine Flow Meter Electronic 3/4" 3/4 inch 10-100L/Min Oil Flowmeter Kerosene Gas Methanol Diesel Fuel Flow Digital Meter Oval Gear Gauge LCD BSPT/NPT with Battery: Amazon.com: Industrial & Scientific
Flow Sensor, 3/4 Inch Male NPT, 3-Wire, Digital Pulse Output, Includes 10kOhm Pull-Up Resistor to VCC, Hall Effect Sensor: Amazon.com: Industrial & Scientific