In addition to ordinary processing, the smoke detector can be checked easily by pressing the test button. In this way, it can be switched off quickly even with a false alarm (which is not yet occurred), without having to be removed first, as with so many cheap version or at least looking for a director. In addition, the smoke detector will flash only when faults and not permanent, what is disturbing, especially in bedrooms. Added to this is an extensive and good description. So top class - I'm going to set it for other rooms which still.