This small & unnoticeable smoke detector operates according to the scattered light principle. Even a small quantity of smoke particles is enough to trigger a loud warning tone (85 d B/3 m) & an optical alarm display (via LED). Furthermore, is conveyed by the radio module of the alarm to all the wireless smoke detector with the same encoding in transmitter. A comprehensive alarm is thus implemented in a simple manner. A very useful test function provides a straightforward & easy verification of the entire device (including the smoke chamber)