jimbert The part number on the box that mine came says FJ3538, so probably manufactured by Fanju. It is advertised here as having an atomic clock, but the manual does not mention it and after being on for a couple days, it is still 40 seconds off. My other atomic clocks update successfully, so I know that the WWV radio signals reach my location. I agree that the temperature and humidity are not very accurate. They both appear to be about 5 deg F and 5% high, respectively, compared to my other sources which I think are correct. It is possible to calibrate the barometric pressure if relative mode is selected. Too bad the temperature and humidity can't be calibrated. It needs to be hacked by someone to make that possible.

jimbert The box mine came in says FJ3538.

jimbert The DC specs are +-(0.8%+5). At 4000 counts, 0.8% of that is 32, then add the 5 and you get +-37. So a 40.00VDC signal, for example, could be measured at anywhere from 39.63-40.37VDC (40.37 would overflow 4000 counts, so would scale to 040.4). So 4000 counts is misleading and useless when only 400 counts are actually meaningful. A quality 4000 count meter like a (very expensive) Fluke is spec'd at 0.1%+1. Having said that, the specs for this meter are comparable to other inexpensive meters and it is still useful, as long as you keep its limitations in mind.