Bests & Worsts Reviews from Amazon

I bought this same hygrometer packaged as Acu-Rite brand from a Mill's Fleet Farm for $9.99 more than a year ago. I've always had it turned on since then, and I've never had to change the batteries. I tested the unit not long after I bought it and again just yesterday (using the NaCl and distilled water test and the Boveda humidipak kit) and after 8 hours the display stabilized at 75% just as it should. I also made a Potassium Carbonate test and it was stable at 43% after ~18hrs. This is great to see from a $10 unit. I've traveled with this product and it has held up through that as well. I've never tested the accuracy of the thermometer, as I mainly bought this instrument to read RH in an instrument (guitar) room, and guitar cases. I've also owned "The Weather Channel" brand weather stations with built in hygrometers that were more than twice the cost of this product, and found them to read more than 10% off when testing. Maybe I got lucky and happened to buy a accurate unit, but from my experience with this I highly recommend buying yourself one. PS I have since had relatives buy these units and they were not as accurate as the one I bought, so I guess I really might have just been lucky. The other units seemed to report higher humidity then existed (when RH was 40%, they showed +3-5%, which is considerable). The plus side is that they don't seem to get worse over time, so if you know the unit to be off by a certain amount, you should be able to predict the actual RH.