Over the years I've tried a variety of digital hygrometers and never been impressed with any. A few that had adjustment never really adjusted. I recently bought two Govee H5101 units and when salt tested they were within 1%. They have a Bluetooth connection and are adjustable in increments of a tenth of a percent RH and degree. I liked them so much I bought two more that are model H5075. I just calibrated the 3rd one and it was within tenths and the 4th is being calibrated now. I have 65% RH SHIELD beads in the humidors and tupperdors and they seem to be holding very well. I hope I've finally found a working solution to humidor maintenance. I got the Govee units on EBAY at what I thought were very reasonable prices, considering all the junk I've bought before. And though they are made in China, I read they use a Swiss-made RH sensor. The 5101 units use a large CR2450 coin type battery and the 5075 uses two AAA batteries. The 5075 is a bit larger than the 5101. I hope they will continue to work.