Mains Powered Optical Smoke Alarm with Back-Up Battery - Kidde Firex Sentry KF21

The Kidde KF21 and KF21R Sentry Optical Smoke Alarms are mains‑powered detectors with an advanced optical sensor, providing early warning of slow, smouldering fires in hallways, landings, bedrooms, and living areas. The KF21 has an alkaline battery back-up and the KF21R, a self-charging lithium battery back-up. Capable of connecting with up to 23 compatible Kidde FIREX smoke, heat, and CO alarms so all units sound together in an emergency. Designed for quick, tidy installation, the KF21 range features a Quick‑Fit Slide‑On Base and a 150mm flared plate to cover marks left by older alarms during retrofits.

• Power: 230V mains-powered with battery backup
• Backup: Optional alkaline or self-charging lithium backup battery versions
• Warranty: 10-year warranty
• Designed for installations in living areas, bedrooms, and hallways
• Interconnectable with up to 23 other Kidde / Firex alarms via cable
• Test & hush button for checking operation and silencing nuisance alarms
• Kitemarked to BS EN 14604: 2005
• Suitable for installations complying to BS 5839-6: 2019 Grade D1 (KF21R) or Grade D2 (KF21)
• Comes with a coloured dust cover (to protect alarm temporarily if dusty works are carried out)
• CE and UKCA marked
• Tamper-resistant locking prevents unauthorised removal
• Supplied with fixings; 2 x screws and 2 x rawl plugs
• This alarm is also suitable for both the Welsh and Scottish updated 2022 legislation