Blue Sea Systems Si-Series 120 Amp Automatic Charging Relay 7610 SI-Series 120 Amp Automatic Charging Relay Automatically combines batteries during charging and isolates batteries when discharging and starting engines Protects sensitive electronics by temporary isolation of house loads from engine circuit during engine cranking 12/24 volt auto ranging voltage input Hermetically sealed contacts/vaporproof Waterproof rated IP67 - temporary immersion for thirty minutes Ignition protected - safe for installation aboard gasoline powered boats Remote LED output indicates relay state away from ACR Supports high-output alternators up to 120 Amperes Dual sensing