Perko Medium Duty Battery Selector Switch - 250A ContinuousMedium Duty Battery Selector Switch 250A Continuous Features: For use with 6 two 50 Volt Marine Electrical Systems Capacity 250 AMPS Continuous, 360 AMPS Intermittent 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 Specs: Diameter: 5 1 4" Depth: 2 5 8" This Perko switch uses a break before make design, allowing you to choose between two