$18.96: First Alert Carbon Monoxide Detector CO400 + CO605 Plug-in Battery Backup CO Alarm at Amazon

Amazon has First Alert Carbon Monoxide Detector CO400 + CO605 Plug-in Battery Backup CO Alarm for $18.96. Shipping is free. Price: $70.02 lower (79% savings) than the list price of $88.98. $6.78 lower (26% savings) than the previous price of $25.74. Customer reviews: 4⭐ / 10 global ratings