The BRK Combination Smoke/Carbon Monoxide Alarm is a new, hardwired unit with a battery backup system for added security. This alarm, featuring a white color and a 5-inch diameter, is designed to detect both smoke and carbon monoxide. With its direct wire-in installation and 9V battery backup, this alarm offers reliable protection for your home. The BRK brand ensures quality and peace of mind, making this combination alarm a necessary component of your home security system.