This FireAngel smoke and carbon monoxide alarm is built to quietly watch over your home for the long haul. Its advanced optical sensor spots real smoke, so there won't be any false alarms. The electrochemical sensor keeps a close eye on carbon monoxide levels and alerts you if they become dangerous. Plus, its clear alarms and visual indicators tell you exactly what the danger is, so you can act fast without confusion.Good to Know - Sleep Easy silences nighttime low-battery chirps for uninterrupted sleep - The large test button makes quick checks easy with total confidence - Its flexible positioning suits bedrooms, hallways and living spaces - It's BSI Kitemark certified for trusted safety and extra peace of mind - A 10-year battery life means no battery swaps for years