Couldn't find the answer to this one on any of the Yong Heng compressor posts or Yuo Tube vids. Just received my compressor today from China, Oct-30, It took less than a week to California; 308$ including shipping, but with no assembly instructions of any use. The temperature meter was included but not mounted and had no batteries in it either. I did figure out where the thermocouple-probe goes into the pump cylinder, but there are no specs for what size or voltage for the 2 button-cell batteries it uses. I guess everyone else got their compressors with the meter already mounted and the batteries installed, so can someone pop out a battery from the back of their meter and ID them for me....I can't try my compressor out until I get some batteries; I Will also need to pick up a 220 volt plug that fits my wall socket;(BTW this one has no auto-shut-off on it either). It looks like I will need a better water separator as well, although I see a lot of guys filling their SCBA tanks with the cheesy little filter that comes with the compressor. My main concern right now though is finding out the type of button cell batteries required for the temp meter. Thanks for any help on that.