I have bought 3 devices. A measuring accuracy of ± 0.1°C is indicated.
I am currently measuring 20.5° / 20.8° / 21.2°.
Seems to me to be quite far away from the stated accuracy...
Mine don't... I bought 3 of them over several years and they all show almost the same reading, only one is 0.1 degrees higher. But it takes a while, you have to let them stand next to each other for 1-2 hours until they settle down. Maybe I was just lucky with my specimens.