Avoid the potentially damaging effects caused by most trickle chargers. Battery Tender® BTP Microprocessor Technology and quick-connect convenience automatically maintains the batteries in all your vehicles so they are ready to go when you are. You just set it, and leave it! Harness accessory for use with multiple batteries. This black quick disconnect works with 12-volt models only. Ring terminal harness accessory for use with multiple batteries. Contains a 7.5 Amp fuse. Length: 2 feet.