First Alert CO615 Plug-In Carbon Monoxide Alarm with Battery Backup & Backlit Digital Display | First Alert
Defender CA6150 Carbon Monoxide Detector
Cheffort Handheld Carbon Monoxide Meter, Portable Carbon Monoxide Detector, Professional-Grade CO Gas Tester with LCD Backlit Display, 0-1000PPM Range for Industrial and Home (Battery Not Included) - Amazon.com