Best Carbon monoxide and natural gas detector

First Alert GCO1 (1039758) Plug-in Combination Explosive Gas and Carbon Monoxide Alarm with Battery Backup

Google Nest Protect - Smoke Alarm - Smoke Detector and Carbon Monoxide Detector - Wired, White

First Alert SC9120LBLA Hardwire Smoke/Carbon Monoxide Alarm 10 Year Battery

Kidde KN-COP-IC Hardwire Carbon Monoxide Alarm with Battery Backup and Digital Display, Interconnectable

Kidde C3010 Worry-Free Carbon Monoxide Alarm with 10 Year Sealed Battery

LSENLTY Portable Carbon Monoxide Detectors Support 500-hour Standby Time, 3-in-1 CO Detector (Temp, Humidity, and CO), Alarm Function, Lanyard Design for Camping Travel Car RV Vehicle Aircraft

LSENLTY Carbon Monoxide Detector, High Accuracy CO Detector with Digital LCD Display, 3-in-1 Air Quality Monitor(CO, Temperature and Humidity Sensor), CO Alarm Detector for Home Kitchen Travel

BW Clip BWC2-M Single Gas CO Monitor

HAKINAKU Portable Carbon Monoxide Detectors [3-in-1] Mini Size CO Monitor with Kickstand & Lanyard Gas Smoke Alarm [ CO Temperature Humidity Sensor ] for Outdoor Camping Travel RV Home Hotel CSA-6.19