Blue Sea Systems SI Series Automatic Charging Relay Features Protects sensitive electronics by temporary isolation of house loads from engine circuit during engine cranking Designed for 12 or 24 volt systems 1224 volt auto ranging voltage input Hermetically sealed contactsvaporproof Waterproof rated IP67 - temporary immersion for 30 minutes Ignition protected - safe for installation aboard gasoline powered boats Remote LED output indicates relay state away from ACR Supports high-output alternato