AMSENTI Sentinel I alarm panels are low voltage (9V) with AC transformer that plugs into 115V wall socket. AMSENTII Sentinel II alarm panels are low voltage (9V) battery powered (battery included). Red light and audible alarm (with test/silence/auto operation). AMSENTII-W alarm panels are watertight for outdoor use. All three models require manual reset of alarms. Thermoplastic enclosure for indoor installation only (on AMSENTI and AMSENTII models). Suitable for use with any dry contact signal. UL listed power supply. Order float switch separately.