First Alert 6-Pack 10-Year Smoke & Carbon Monoxide Alarm

6-Pack 10-Year Combination Photoelectric Smoke & Co Alarm Contractor Pack. The SMCO210 10-Year Sealed Battery Combination Smoke & Carbon Monoxide Alarm with Slim Profile Design uses First Alert's Precision Detection advanced sensing technology and meets new industry standards. This 2-in-1 alarm provides convenient protection against both fire and carbon monoxide (CO). Also equipped with a 10-year sealed battery to eliminate the need for battery replacements and low battery chirps.