I have the Xikar ones as well.
One word of unasked for advice though, I wouldn't salt test whatever you get next. Whatever media method you use, beads or boveda, etc. I would throw the hygrometer in a ziploc with that instead of the salt. The salt test, if done correctly, gives out about 75% humidity, if I remember correctly. That's great if you keep your humidor at 75%, but I sure hope you don't.
You should calibrate your hygrometer as close to the rH you're looking for because the further you get from your calibration point, the further off your reading will be. As in, if you calibrate at 75%, but are looking to keep 62% your measurement at 62% could be WAY off the actual.
This all makes sense in my head, but sometimes I don't articulate my point very well. If anybody has any questions, let me know.