Battery Selector Switch Replaces Guest 2111A 4 Position for Marine Boat Camping The selector switch will allow the use of one battery for engine starting and one battery for auxiliary electrical equipment. Batteries may be placed in parallel by switching to (BOTH) for emergency usage Small in size, Fine appearance, Sturdy and durable Can be installed in any position BOTH- Operation of both batteries and banks of batteries This product is 100% brand new and comes in original color packing