You can not mount a smoke alarm more easily than this You do not have to think about whether a power line may be located at the desired mounting location, because there is no drilling Magneto link is suitable for all current models of smoke alarms (from &732; 80 mm.) & consists of two thin, self-adhesive metal disks One of them is stuck as a carrier plate to the ceiling, while the other magnetic disk is mounted on the smoke detector. A secure hold on the ceiling & light maintenance of the detector is ensured thereby. Dim.: (&732; x H, the metal plate) 71 x 2.2 mm.