For maintaining voltage continuity to engine computer, clock, and radio memory when vehicle battery is disconnected. Retains radio presets, ECM codes, and learned procedures up to four hours. Plugs into vehicle's cigarette lighter outlet. Uses 9 volt battery (not included). Manufactured by Performance Tool, part number W89203. All items are sold as shown. Since we offer free shipping we will ship the items the cheapest most cost effective way possible.
