The device is working properly. I have the temperature checked with an external termomether and with little tolerance it switches off at the set temperature. One, large for me downer is, that's not illuminate the display. The heating depends on us in a darker "edge" and if I want to set the temperature as (My wife and I have different ideas of hot :-)) I always have to use a flashlight. Schade eigendlich, for a few cents more, a LED would have been possible. Therefore, a point deduction from the B mark.