Perko Heavy Duty Battery Selector Switch w/Alternator Field Disconnect

• Diameter: 5-1/4"
• Depth: 2-5/8"
• Polycarbonate Body with Brass Terminals
• Ignition Protected
• For use with 6 to 32 Volt Marine Electrical Systems
• Capacity - 250 AMPS Continuous, 360 AMPS 5 Mins. Intermittent
• Terminal Stud Size: 5/16"
• When used with Non-Unitized Alternators, these models will interrupt the field current (reducing the possibility of damage) if turned "OFF" with the engine running.

Quick guide: https://productimageserver.com/literature/quickGuide/33120QG.pdf