Let Safe-T-Alert alarms protect you from hidden dangers on the road. Alarm has been designed for the Rugged RV Environment. Ideal for Class A Motor Homes, Class B Van Campers, Class C Mini-Motor Homes, Travel Trailers, Fifth Wheels, Truck & Folding Campers.• Fully Operational During Mute. Mute does not override detection circuit, giving you full time protection.• InteleCheck Circuit. No false alarms from temporary exposures to LP Gas/Propane, aerosol cleaners, hair spray and other flammable gases.• Micro Current Technology. Saves precious battery power.• Long Life, Self Cleaning Sensor. Maintenance free built-in sensor.• Loud 85 dB Alarm. Alerts you to the presence of hazardous propane vapors. Test/Reset Button. Used to temporarily silence alarm during ventilation. Tests all the detectors functions with one touch. REPLACE ANY CO AND PROPANE ALARMS/DETECTORS IF;The CO Alarm is over 5 years old.*The Propane Alarm is over 5 years old. The Alarm that fails to test properly. Important! Only install CO and Propane alarms that are UL listed for Recreational Vehicle Use. Some CO alarms or their replaceable CO sensors may have a shorter service life. Check the manufacturer's owner's manual for replacement information. Self-cleaning sensor | MTI Industries Safe-T-Alert Propane/Natural Gas Alarm - Flush Mount, White