The good performance in the Stiftung Warentest (issue 1/13) has given rise to this smoke detector. The alarm is loud enough so we do not go out (in a detached house with a basement) of the need for networked detectors. The installation is quite simple. I have a total of 12 detectors mounted. There is the PX-1 but obviously in two versions: one-time (the one warming up by candle, spread across the (magnetic) mounting plate that can then festglebt on the ceiling) with supplied hot glue; the (better) is the alternative sensor with an adhesive layer that is mounted on the mounting plate). The second shipment (of six detectors) contained the adhesive layer and facilitated the installation thoroughly. From the item description but I could not see this.