Optical smoke sensor suitable for living rooms, bedrooms, hallways and landings 230V mains powered with battery backup (3 x AAA alkaline batteries (supplied) Hardwire interlink up to 15 FHN250 smoke alarms and FHN450 heat alarms in the same system. PLEASE NOTE: THESE FHN SERIES ALARMS ARE NOT COMPATIBLE WITH THE OLDER FH MODELS X-Profile sensing chamber ensures the quick detection of slow smouldering fires and fewer false alarms Fast-Fix mounting base design uses Push-Fit connectors for a quick installation and additional safety when removing alarms for cleaning and replacing batteries Thermal Stability Enhancement (TSE) Technology for improved fire detection End of life warning chirp can be silenced for up to 10 hours. Large test and silence button for easy testing, maintenance and silencing Suitable for installations complying to BS 5839-6 Grade D2 UKCA marked, CE marked, and Kitemarked to BS 5446-2: 2003 Warranty: 6 years manufacturer's warranty (not including batteries) PLEASE NOTE: these FHN series alarms are not compatible with the older FH models, Weight: 0.43210603352 pounds, Manufacturer: Firehawk