First Alert, 10-year Battery Smoke and Carbon Monoxide Alarm, 2-pack

First Alert Precision Detection 10-Year Battery Smoke & Carbon Monoxide Alarm, 2-Pack — Combination alarm designed to detect both smoke and carbon monoxide; precision sensing technology helps reduce nuisance alarms while maintaining fast detection; sealed 10-year battery eliminates battery replacements; end-of-life alerts signal when replacement is needed; twin-pack supports whole-home safety coverage. 10-Year Sealed Battery, End-Of-Life Warnings to Replacement.