Blue Sea BatteryLink Automatic Charging Relay - 12V/24V DC 120AFeatures: 120 Amp continuous rating; 12/24V DC auto ranging voltage input; Senses charging on two battery banks; Side and bottom knockouts for cable connections; Clip-on cover insulates terminal connections; 7/8" (22 mm) stud length to accept multiple cable terminals; Integrated LED indicates ACR status; 1/4" A- .032" male quick connect terminals for ground and optional features; Largest battery bank cannot exceed Group 27;