Dual Carbon Monoxide / Propane Gas Alarm. Double your protection by replacing your old propane alarm with one alarm that detects two threats to your safety. Dual alarms detects both carbon monoxide and LP gas inside your RV. Also detects CNG. 12 volt operational range 7-16 volts. No false alarm senor technology. UL/CSA listed. 5 year warranty. Flush mount: 6 1/2"W x 3 1/2"H x 1-1/2"D White.