I have attached eienen heat detector in miniature for the kitchen with ELRO RMAG3. That was no problem at all as in the other 3M based magnetic attachments. Unfortunately, the part is a little too large for the heat detector CAUTIEX INVISIBLE 10 years. The only looks like the small ELRO smoke detectors. The plate is about something. 7cm they did not anyway. However, since the information seemingly everywhere "approximately" are, should not be the problem of the seller.