Kidde Firex KF20 Hard Wired Mains Optical Fire Smoke Alarm 9 VBattery Backup
With 9 VBattery Backup. Kidde Firex KF20 Hard Wired Mains Optical Fire Smoke Alarm. The updated Kidde Firex KF20 alarm is a mains powered, interconnectable optical smoke alarm that use up to 70% less energy than previous Firex models.