At first I was skeptical that this may hold. Our ceilings are papered and painted woodchip and then the cheap price .... but the magnetic attachments KEEP really great. We have the two magnetic disks as described one glued to the ceiling and the other on the detector and then to after a day with each other, so that the double-sided tape can develop its adhesive effect (this way it has to be made even with adhesive hooks ...). Lo and behold, it hangs and hangs ... I would recommend the fixing each ... does not want to drill
