Western Caliber III. No calibration required. Checked it against a Humidipak 75.5% Calibration Kit. At 24hrs it read 75%, and at 35hrs it read 76%.
However, that's in the zip-lock bag with my cigars right now so just the analog during seasoning, which I've calibrated about 3 times with the Humidipak and got it pretty close to my digital, although not as responsive/reliable.
I would never base anything off of an analog.