FIRST ALERT Plug-In Carbon Monoxide Detector with Battery Backup, 3-Pack, CO605The First Alert CO605 Plug-In Carbon Monoxide Alarm with Battery Backup utilizes an electrochemical carbon monoxide sensor to accurately and effectively warn you of elevated CO levels. The plug-in design and included battery backup mean your space can be continuously monitored for dangerous carbon monoxide gas, even during power outages. Simply plug the alarm into a 120-volt outlet, and the personal carbon monoxide detector is ready to go. When CO levels rise above a safe threshold, a loud 85-decibel alarm alerts you to the threat. Designed for simple use, the CO detector has just 1 button that silences or tests the unit, as well as an end-of-life timer that lets you know when it is time to replace the device.Simple and Easy to Use: The carbon monoxide monitor is easy to set up: simply plug it into a standard electrical outlet to monitor your space for carbon monoxide. There are no complicated displays or settings to navigate; a single button silences the alarm and tests the CO detector.First Alert BRK 9120B6CP Hardwired Smoke Alarm with Backup Battery, 6-PackThis 6 pack of First Alert hardwired smoke alarms includes a 9 volt battery backup that continues to protect you in the event of a power failure. The detector features an ionization sensor for detection of smoke and fast flaming fires, as well as a loud, 85 decibel alarm. One button silences any nuisance alarms, and also tests detector functions, while lights indicate if the alarm detects smoke. The latching alarm indicator automatically identifies which unit initiated the alarm, even after the conditions that set off the alarm have subsided. And an end of life signal enhances your safety by letting you know when it's time to replace the unit. Connect it to compatible BRK or First Alert alarms within a single family residence. When one alarm is triggered, all connected alarms will sound.NOTE:The product is a hardwired alarm, also confirm if the wiring polarity is correct and that all wire nut connections are secure. A loose neutral (white wire) connection within the home junction box could prompt a device malfunction. First Alert 120 Volt Wire-In with Battery Backup smoke alarm in 6 pack contractor pack