Perko Medium Duty Main Battery Disconnect Switch w/Alternator Field Disconnect & Key Lock One Size. This battery disconnect switch manufactured by the experts at Perko features an alternater field disconnect (AFD) feature and a key lock. With a 250 AMP draw Perko's Medium Duty Main Battery Disconnect Switch is a cost effective and safe means of protecting your starting batteries. For use with 12/24/32V electrical systems Perko's Medium Duty Main Battery Disconnect Switches provide the extra capacity needed to safely disconnect the start and run (or remote) batteries from each other. And with the extra effort you make during off you're reducing the run time of your electrical system which means you're using it less which is better for the next person who goes overboard. Specifications for Perko Medium Duty Main Battery Disconnect Switch w/Alternator Field Disconnect & Key Lock: Manufacturer: Perko Amperage: 250 amps Color: Black Features of Perko Medium Duty Main Battery Disconnect Switch w/Alternator Field Disconnect & Key Lock AFD: Yes Lockable: Yes Continuous Amperage: 250 Package Contents: Perko Medium Duty Main Battery Disconnect Switch w/Alternator Field Disconnect & Key Lock Perko 9604DP: Medium Duty Main Battery Disconnect Switch w/Alternator Field Disconnect & Key Lock One Size