Flow Meter -3/4 Inch NPT Aluminum Alloy Digital Fuel Meter Water Flow Meter Mini Digital Turbine Flowmeter Diesel Fuel Flow Meter 5-100 L/Min

Well nothing prevents you to use it on air or any other gas, provided that you calibrate it. And it's quite easy to do so, despite having only 2 buttons.However, the biggest problem is the metal chips still remained from the manufacturing process, and they could damage your installation downstream. While they are fairly inexpensive, a cleaning process must be done and your time will be spent.

Produce working well

This is a fairly decent water/fuel flow meter/gauge that appears to be fairly well-constructed without visible defect and for the most part it works as expected without issues (so far). It's fairly hefty and slightly larger and bulkier than expected although it also seems sturdy that can take a beating (well, within reason). It's a significant upgrade in comparison to what I had from Home Depot/Hardware with respect its physical build quality; however, I'm particularly thrilled about the quality of the LCD (more on that).✘ Note that it comes with a note indicating that there might be residual diesel in the flow meter as part of the quality test and while I do appreciate that, I still believe products like this should be thoroughly cleaned prior to leaving the factory regardless what's being done to it (QA, test, refinement, whatever) so I don't have to clean it. The fact it's unclean as a result of QA or any other appropriate/standard processes is NOT, in my mind, an excuse to not have it cleaned.It has all the common features (or modes) that you'd typical find from these relatively compact water/fuel flow meters such as flow rate (Litres, Gallons, Quarts, Pints, or Cubic Metres) modes or total/cumulative volume mode; however, it also lacks certain features that some others have such as interval, last-x days and so on. It's powered by an internal battery but it's unknown to me exactly what type it is since it's not documented anywhere (btw, many others use standard CR2032). What sets this apart from some others though is that it's entirely made of aluminum and not just the inlet/outlet (and mine were plastic) although a few others are made of brass which is superior to some (I'm fine either way).The LCD is moderately easy to read although it can be a bit difficult to read at times especially at certain angles and the overall quality and usability is probably the biggest downside for this flow meter which is a shame. The measurements (volume) seem reasonably accurate although I haven't gotten the chance to test 'em for real. With that being said, the total volume is fairly accurate based on some quick tests and I can only hope the flow rate is equally accurate although admittedly I'm not overly concerned about the flow rate at this point in time.I should also mention that I have had several of these in the past and still have a few currently, and these meters tend to lose their accuracy overtime for some reasons and they can actually be off by quite a bit (which was one of the reasons they were tossed). Note that this particular flow meter can also be calibrated although the mechanism is rather crude in my eyes. We shall see how long this will last. Fingers crossed!≡ ValueAll things considered, this is a reasonably decent water/fuel flow meters/gauge that seems fairly well-constructed (aluminum alloy in its entirety) and for the most part works as expected without issues although the LCD screen leaves a lot to be desired. It's a bit pricey at $52 for what it provides and its overall build quality, usability, versatility, and performance. Its longevity remains to be seen, as always.