FX-4 Carbon Monoxide Alarm - 2-PackMarine Use - Low Voltage Hard Wired Alarm. Replaces your CO alarms that are over 5 years old. No Bags. No Tags. Full 5-Year service life, longer than CO Sentinel CMD-4M alarms. CMD-4M and CMD-3M that have reached end of life. Features:Conforms To ANSI / UL STD 2034 - MarineMeets ABYC A-24. NMMA Listed ComponentMost ReliableBoats DC electrical system or marine grade batteries supply power to the alarmNo missing or dead batteries to replaceProven Sensing TechnologyPrevents nuisance alarms which could lead to confusion and disconnected detectorsAdvanced TechnologyAlarm Mute button with advanced technology that silences alarm while boat is ventilatedRapid recovery sensor resets when silenced or reactivates alarm if dangerous levels of CO remainLoud. 85 dB alarm alerts you to CO dangerCase Size: 2.5"W x 3.5"H x 1.25"D