I wasn't sure how to price this item to I put it on ebay Auction. http://www.ebay.com/itm/West-Mountain-Radio-PWRgate-PG40/152702448936 It allows you to hook up both a battery and a power supply to your radio. The battery backs up the radio if the power supply no longer has electricity. The power supply will charge the battery if the radio is off. Rated at 40 amps.