Very difficult to read without sufficient light and looking at it straight on. I calibrated this with 2 other units (different models) and this was the least accurate of them all. I would suggest the Cigar Oasis Caliber IV Digital Hygrometer or the Quality Importers HygroSet II Round Digital instead. Both of them calibrated very well and they are very easy to read.

Used a boveda calibration kit when I got it and it was right on 75. Spend a little extra and get a caliber, you won't be sorry

I like it, but I did have to reference the instructions to YouTube videos just to make sure I was doing it right.

The hygrometer itself works perfectly and just as advertised. I used used a Xikar Humidity Bead Gel Jar to test the calibration and it was perfectly calibrated already, after about an hour in a ziplock bag with the gel jar it read 70% which is what the Xikar Jar listed humidity would read. I left it in the bag overnight just to be sure and it continued to read a solid 70%. After that i added it to my humidor and got a solid reading of 68%. The only reason i gave the hygrometer 4 stars vice 5 is because it is true (the other reviews) it is very difficult to read if you're not viewing it from an angle (you won't have this problem if you have it mounted to the top-opening lid, mine is a glass case which is why i can't lid mount). Head on is pretty much impossible as you'll see all sorts of digital lines. Also of note... I thought it had to be calibrated because i was mistaking the bottom temperature gauge for a humidity gauge, but upon further inspection i realized i was an idiot and totally missed the humidity reading line which points to the humidity level. Good buy, for an out-of-the-box ready, accurate, and aesthetically appealing hygrometer.

This works well, is accurate enough, is easy to set up, and attaches to the inside of your humidor with a magnet for easy removal. The only complaint I have, is the LCD is difficult to see if you're looking down at it from an angle (as you usually will be). To see it well, you have to be looking at it within a small angle of straight on. This is only an issue because my humidor is sitting on a moderately low side table. Not a big issue, and I still recommend this product.