Compressed air line dew point checker.
Check your dew point on you compressor air line to see where the dew point is and avoid water contamination.
Double checked the reading on this with my newer unit and it was spot on.
Someone left batteries in it too long and damaged the one battery terminal but I cleaned it and it works fine. Just doesn't look so clean and shiny anymore. Also works fine from the power supplies included. I have not tested or ever used the data connector. No idea how that needs to be set up or what software needed.
Read More on eBay