UEi PDT655 is very nice and accurate
The device is somewhat on the larger size, but for most users this is a plus. Its length is 6 inches and the width is 1.5 and it about ¾ inch thick. It will fit in a pocket but there will be no hiding it there, too long for that. However, it’s actually about ½ inch shorter that the Samsung phone I carry. The readout numbers are ¾ high and easy to read from 10ft away with good lighting. The display does light up, but only for about 4 seconds, just long enough to see the number if you’re in a dark basement or attic. The probe length is 5 inches and has enough mechanical resistance that it holds the position as you place it into a vent or hole. I was able to hang it onto a vertical return grill by the probe only, since in this case the grill was aluminum. The built-in magnets will hold it nicely on a flat metal area but probably not on a round duct. On those you could easily hang it by the probe though. It uses 1 CR2032 battery which helps keep the weight down. It’s a common enough battery that big box and drug stores sell them and they are cheap. It will self-power off after one hour, a nice feature, but it also means that any readings you have also disappear. It updates very quickly and follows the temp rise in a duct very near real time. It followed the rise I saw with my Fluke thermocouple and I was impressed with that. Accuracy seems reasonable and matches up nicely with other thermometers that I believe to be accurate. See photo Read more
