Rather more expensive than others, it has been well noted by a consumer association. We can only trust them ... The batteries are supposed to last 10 years (I guess Bosch relies on the device's consumption to affirm that?), But what batteries last 10 years? The downside is that the screws are threaded up to the head, and are therefore inappropriate if your ceiling is plasterboard (the threaded portion will end in the blank)! You can get away using small brackets to the ceiling away from the detector ... or changing screw. These supports are made so that the screws are working, but incidentally they allow. Unworthy of a "big" brand!
