Features  Comprises a built‐in alarm indicator (LED)  Proven technology Applications Smoke detector for detection of combustion gases, mainly consisting of visible (large) particles. The detector is not influenced by electrical radiance from mobile telephones etc. The standard version and S‐version comprise a built‐in alarm indicator (LED). For use with Autronica type BS‐ fire alarm panels. Principle Measurement of reflected infrared light in a measuring chamber.