SMOKE DETECTORS FOR HOME: The optical smoke alarm makes protecting your home simple. Its optical sensing chamber 'sees' smoke as it enters the alarm, providing a fast response to slow burning fires with thick white smoke. FEWER NUISANCE ALARMS: The advanced optical sensor ensures the FireAngel smoke alarm is less prone to false alerts from cooking fumes. Avoid placing near bathrooms or kitchens. 10-YEAR BATTERY: Each smoke alarm is fitted with a 10-year sealed battery, offering protection for the lifetime of the device without needing to change the batteries. QUIET SELF TEST: Check the smoke alarm by just pressing the button, without the full-volume siren. It uses a reduced-sound test for less disruption EASY INSTALLATION: Fitted with a removable base plate, secure it to the ceiling using the screws provided. Push and twist to secure the device. The base plate is identical to the ST622, making replacements quick and easy. SAFETY ASSURED: The FA6620 smoke alarm holds UKCA marks and is certified to BS EN 14604:2005+AC:2008