...and it got within 2% of the given 75%, which is really good for an analogue device.
Since I didn't use distilled water and temperature was a few degrees below 20, which can cause variations in the absolute relative humidity salt causes, that's even better accuracy than some very expensive calibrated hygrometers (typically +/-3%) can achieve.
I ordered this analogue device along with a digital TFA Climate Guard and two small digital TFA Electronic Thermo-Hygrometers (to go in guitar cases) Thomann are offering and am impressed with the accuracy of all four, none more than ~2% off.
Made of plastic so very lightweight but looks the part and does its job well.