Battery Switch isolates Start and House circuits, reducing the chance of fully discharging both batteries. This isolation also protects electronics from engine starting sags and spikes. Ignition protected system is safe for installation aboard gasoline-powered boats. Accepts up to 4/0 battery cables. Tactile textures indicate knob position by touch alone. Simple on/off switching in normal operation (with an ACR or isolator installed). Meets American Boat and Yacht Council (ABYC) requirements for battery switches. Fits all Perko and Guest low amperage battery switch hole patterns. 7/8" stud length to accept multiple cable terminals. Reinforced polycarbonate case design allows surface or rear panel mounting. 32V DC max. 300 amps continuous rating. Automatic Charging Relay (ACR) combines batteries during charging and isolates batteries during engine cranking and when not charging. Supports high-output alternators up to 120 amps. Features built-in LED lights to indicate when batteries are combined. Waterproof rated IP67. Senses charge source on either battery bank. 120 amps continuous rating. Lifetime warranty.