The dispatch has indeed lasted two weeks, but a pack of gummi bears was paid, so I have nothing to criticize here :) The assembly of the smoke detector works perfectly well.
My only real problem are the Magnetopads simply stick is not strong enough to hold the quite high weight of the smoke detector. On the first attempt came despite very strong pressing of the pads on the ceiling the smoke detector after 30 minutes back down. I then tried again, this time with double-sided tape between Magnetopad and ceiling. This time kept the whole though, after all, for a day but again fell off the smoke detector.
I hereby Magnetopads unfortunately not at a friend because they do not have enough adhesive strength for the intended use. Whether the smoke detector has survived the two-time event harmless from 2.50 m I have not yet tested.