Maretron Carbon Monoxide Detector f/SIM100-01 [CO-CO1224T]Attaches to Maretron SIM100 for NMEA 2000 network monitoring Real Test technology allows for functional testing in the field Trouble relay for circuit trouble or detector end of life notification Provides wiring supervision 4 wire detector; mounts to wall or ceiling WARNING: This product can expose you to chemicals including NICKEL (METALLIC) which is known to the State of California to cause cancer. For more information go to P65Warnings. ca. gov.