Reliable detection: Built-in photoelectric sensor identifies smouldering fires promptly while reducing false alarms throughout the home Loud acoustic signal: Sounds an 85 dB warning tone at 3 m distance so residents across each floor are alerted immediately to potential danger False alarm hush: The integrated test button lowers sensitivity for 10 minutes when cooking fumes occur and enables routine monthly operational verification Battery status alert: Emits a brief audible sound when the replaceable 6F22 power cell needs renewal after its 1-year service life Multi-storey placement: Designed for ceiling installation in hallways, staircases, and living areas with a security pin that prevents mounting without an inserted power source