I was watching a episode of mythbusters from season 11 and saw them using one of these gauges to monitor nitrogen pressure in an ice hail gun. I looked it up and it has diaphragm that allows you to measure pressure on all kinds of stuff water, sea water, refrigerants, oil, and air. Anyone use them?

I would not dare use my digicools to check differential water pressure on a chiller but, this could and pneumatics too. Anyway looks cools.