First Alert SC9120B Carbon Monoxide Alarm, Alarm: Audible, Electrochemical Sensor, White

The first Alert BRK SC9120B hardwired combination smoke and carbon monoxide alarm uses an electrochemical carbon monoxide sensing technology and ionization sensor for smoke detection. It includes a 9 V battery for continued function in the event of a power outage and it features a test/silence button, tamper-resistant locking brackets and a universal mounting bracket. This carbon monoxide smoke detector can be connected to other compatible BRK and First Alert hardwired smoke and carbon monoxide detectors. Its latching alarm indicator auto-matically identifies which unit initiated the alarm even after the conditions that set off the alarm have subsided.