Kidde Hardwired Photoelectric Smoke Detector Alarm AA Battery Backup 5-Inch. Experience the next level of fire safety with the Kidde Hardwired Photoelectric Smoke Detector Alarm AA Battery Backup 5-Inch model 20SAR that uses photoelectric sensor technology to detect visible fire particles associated with smoldering fires. New 9th Edition sensor technology reduces false alarms often caused by cooking or shower steam while internal components of the smoke alarm self-test to ensure that it s always operating as expected. (Self-testing is not a substitute for a manual push test of the alarm. Perform a button test once per week to verify proper alarm operation.) The Kidde Smoke Detectors 5-inch design provides smoke detection for all living spaces such as your basement living room bedroom kitchen den bathroom or crawlspace. When smoke or fire is detected an 85-decibel alarm will sound and a red LED light will illuminate. The Kidde Smoke Alarm is also equipped with 3 LED indicators that illuminate b