I got an email that Xikar has a new recalibratable hygrometer. To recalibrate, you must remove and reinstall the battery. This puts it into a recalibration mode. Then they advise the salt test, and while the hygro is still in the bag with the salt, you press a button to reset it to 75%.
Honestly, I dont like it. The Bovedas and Humidipaks are best for recalibration. I am an expert at doing the salt test, but many people screw it up. There is nothing more precise or easy as the Humidipak products. The Hydrasets sold by vendors on this site are a better thought out Hygrometer. Besides the salt test, you can use any Boveda or Humidipak to accurately recalibrate a Hydraset.
Just my thoughts on a new product that will be available soon.