pH meter- male fitting?

I'm looking for a pH meter/sensor that has a 3/4" male fitting. Has anyone ever heard of one of these? I know they have temperature gauges and pressure gauges, but I'm having trouble finding one for pH levels. Here's a picture of a temperature gauge:



Need the same thing but for pH...

As far as I know, to measure pH, you either need a chem lab, or an electronic circuit...I do not know of any mechanical device that is similar to a pressure or temperature gauge. Any one that uses a chemical change (like litmus paper) will likely fail relatively quickly whereas the temp/pressure gauges could last for decades. IOW, good luck, I don't think you'll find one readily available, at least one that is relatively inexpensive and it will likely require power (maybe battery, if you're lucky, but then you have to change it periodically).