Combination 120 volt AC smoke and carbon monoxide alarm with 9-volt battery backup, Interconnectable with all BRK smoke and CO alarms. It eliminates the need for two separate electrical boxes, saving installation time and materials. Separate visual and audible smoke and CO indicators eliminate confusion. Controls can silence the low-battery chirp for up to eight hours or temporarily silence an unwanted nuisance alarm. Intelligent Sensing Technology helps reduce nuisance alarms. Latching alarm indicator, mounting bracket and battery drawer locks. The alarm meets building codes where AC/DC smoke and carbon monoxide alarms are required, either separately or in combination. 5 year limited warranty.