Quick delivered, unpacked and:
Nope, it was too kalt.Das device showed an error.
So leave it for now.
A slide switch on the unit allows for a use as a room thermometer, the other position to use as persons / thermometer. After about 2 hours. I ventured the first measurement in the bedroom.
The temperature enstsprach exactly those that appeared on another room thermometer.
Next, I tried the temperature measurement at me from myself.
Also went smoothly and showed me a normal temperature.
Here I have used no second measurement as equivalent.
So I am of the opinion that this instrument measures exactly enough.