Fireboy-Xintex CO Alarm 12/24V DC - Black [CMD6-MD-BR]CO Alarm 12 24V DC Black A Carbon Monoxide (CO) detector should be installed in each accommodation space. Small crafts or RV's with an open design may require only one (1) detector for adequate protection. If two (2) or more sleeping areas or spaces are partitioned, then one (1) detector should be installed in each of the spaces. The Fireboy Xintex CMD6 M Series CO alarm uses a sensor operating with a microprocessor to measure Carbon Monoxide (CO)