Thats how mine is. Basically to calibrate mine I set my freezer temp and set it in there to see how far off it would be and salt test for humidity. Just adjusted from those readings.
I have that exact one been using it for several years its a good one. The ONLY reason I don't have it in my incubator is because I use ones with probes to free up an egg space. If they have that one get it. I know they all read different but mine is pretty dead on humidity and temp wise. I'm...