The First Alert BRK 1046884 is a combination smoke and carbon monoxide alarm that uses ionization sensing technology for smoke detection. It does not have dual sensors (photoelectric and ionization). If you want a smoke and carbon monoxide alarm with dual sensor technology (both photoelectric and ionization) and a 10-year battery backup, here are some good options: Recommended Dual Sensor Alarms with 10-Year Battery Backup First Alert BRK SM310 Dual sensor (photoelectric and ionization) Powered by a 10-year sealed lithium battery Features test/silence button and end-of-life signal First Alert BRK 3120B Dual sensor (photoelectric and ionization) Hardwired with 10-year battery backup Interconnectable with other alarms Features test/silence button and end-of-life signal These models provide enhanced detection by combining both sensor types, which helps reduce false alarms while improving safety.