Atwood 31011 RV Carbon Monoxide and Propane Gas Detector - 12 Volt
Carbon Monoxide/Propane Detector - Black - Jazz Sales
DC 12V Natural Gas Detector,Propane Detectors for Home,Natural Gas Propane Leak Alarm for Home Kitchen, High Sensitivity Natural Gas Propane Leak Detection (12V-Relay Output) - Amazon.com
MTI Industries 25 Series 12-Volt Safe-T-Alert Mini RV Dual Carbon Monoxide/ Propane Alarm in White 25-741-WT - The Home Depot