Portable Digital Gas Mass Flow Meter Gas Air Flow Rate Tester with 0-200L/min | eBay
Water Flow Totalizer and Flow Rate Meter with Digital LCD Display +G1/2" Hall Effect Liquid Water Flowmeter Sensor-1-25L/min: Amazon.com: Industrial & Scientific
Flow Rate Meter | Sensor Meter - G3/4 Hall Flow Rate Meter Temperature Measurement - Aliexpress
G1/2" Flow Rate Water Sensor Meter+lcd Digital Display Control Total Litres Hall - Flow Meters - AliExpress