Xikar sent me some to replace some old ones I had that never worked right, this is how I had to setup the new "pre calibrated" hygrometers:
1.Place new hygrometer in a sealed bag with a boveda pack
2.Wait a day or so until you are confident that the hygrometer has adjusted and is reading the humdity
3.Note that the hygrometers are all over the place and are in the range of +/- 7 off from the correct RH even though Xikar guarantees +/- 3
4.Since you don't want to be bothered by paying to ship these back to xikar and wait another couple weeks to repeat this process, continue to step 5
5.Make a note on a small piece of paper as to how far off the hygrometer is from the correct rh
6.Tape said piece of paper to the hygrometer
7.Place hygrometer in humidor