Combo Carbon Monoxide Propane Alarms Flush Mount – Black. Have a safe TRIP! Test and inspect the Propane and CO alarms installed in your RV every week and replace malfunctioning alarms. Replace all Propane and CO alarms that are 5 years old or older. Install alarms listed for RV use. Prevent accidents by teaching family and friends about the operation of the alarms. Never ignore a sounding alarm.Features: Double-duty alarm – Detects both gas leaks and CO gas simultaneously. Reliable – 12V power means no missing or dead batteries to replace. Durable – Built for the extreme RV environment. Approved – Meets RVIA/NFPA requirements. End of Life Signal.