Smoke Detector & Fire AlarmGeneral Purpose Smoke Detector & Fire Alarm for Boats & RVsMeets the requirement of NFPA 302 stating that "All vessels 26 feet or more in length with accommodation spaces intended for sleeping shall be equipped with a single station smoke alarm that is listed to UL217 RV for recreational vehicles..."Dimensions: 4.25" Diameter, 1.75" heightAlarm 85dbListing: UL 217 RV Complies with U.S. Coast Guard Section 28.325(b) and Section 181.450 inclusiveUses the ionization principle of detection for detecting fast-flaming fires which consume combustible materials rapidly and spread quickly9V battery operated (battery included); no wiring required for easy installationLow battery alarm features audible beeps to indicate a battery replacement is requiredIncorporates an internationally recognized horn signal for evacuation. During the alarm mode, the horn produces three short beeps followed by a two second pause and then repeats.Features a test button that is easily accessible on the cover of the alarmRecommended installation is to install one unit in each sleeping accommodation, salon, galley, engine/generator room, and electrical control roomSuitable for marine and recreational vehicle use