Works without any problems for a long time. Stable and loud. Adequate for my purposes. Verbessrungsmöglichkeiten: the label (time scale) is only "painted" and becomes weaker with time / faded completely. Notches (or better color) would be helpful. For me, it has also done a waterproof marker (Edding) - who also holds back some time. The magnet at the back is quite convenient to fix the part to equipment or doors, but was somewhat weak. Could be a little stronger, otherwise ends the part with the ringing on the floor, when the ground is only appliances sheet (what the alarm but endures - tested several times).