Precalibrated Humidity and Temperature Indicator with External Probe

The thing about home hygrometers is that it's always difficult to know just how accurate they are. In my air conditioned house in Virginia this one usually reads between 56-60% RH. The tiny, very cheap ones that we all put in our jars with cannabis range from 63-68%. I believe that is too high, so I compare them with this one, which I believe is the most accurate.