DIGITEN G1.5" Water Flow Sensor, Hall Effect Sensor Flow Meter Flowmeter Control 5-150L/min - Arduino, Raspberry Pi, and Reverse Osmosis Filter Compatible

It seems to work, but it rattles at certain flow rates, when you use air to rotate it. Probably not an issue when in a fluid.Also, doesn't have a pull-up resistor, so you can use it for 3.3V MCUs as well, while supplying the sensor with 5V

This one I ordered is the same as the 1/2 inch one and neither come with ANY manual or information about hooking up to "Arduino, Raspberry Pi" as the preview suggests it works with. Trying to find "sketches" for these computers is a bit of a problem unless you are already VERY familiar with them. Just getting an LED to flash showing it's counting is not what is needed, but a separate "sketch" (Arduino programs are called these. for hooking the meter up AND one to run a display (to count) AND getting the meter to talk to the computer and display is going to be above many of us that don't dally with these computers daily. It is well built and will probably work fine once I figure out the software. This is why these are inexpensive compared to those units that come with a display.