Yellow Jacket 69008 Digital Psychrometer - Handheld Humidity & Temperature Meter for HVAC, Industrial, and Indoor Air Quality Testing

The yellow jacket digital psychometer is a piece of junk, total rip-off. This is one where yellow jacket essentially abuse there name in the HVAC industry. Very, very slow response time, not sure when I actually have the right temperatures. DON'T BUY IT.I have three other devices that all agree within about 3 percent RH, and a couple of degrees F with each other. Yet my Yellow Jacket, which cost far more than my other devices, measures 12 degrees F cooler, and an RH of 6% higher than the highest other reading. And I can tell that the temperature reading on the other devices is about right; the Yellow Jacket says it's much cooler than it obviously is. The manual (just a page long) does not give any indication if there might be a way to recalibrate or reset the unit (and I have replaced the batteries with new.) Chinese junk.