Best Seller | First Alert Battery Photoelectric Smoke & Carbon Monoxide Alarm in Gray | Wayfair 1039839 The First Alert Battery Photoelectric Smoke and Carbon Monoxide Alarm detects both smoke and carbon monoxide. It is a wireless-enabled battery-operated detector that features an 85-decibel siren plus a voice alarm to let you know where the danger is.... more | | $74.52 FREE shipping go to store |