Maintain the charge on your vehicle's battery using the included DeWalt 20 volt lithium battery pack or one of your own. The DeWalt DXAEOBDK Battery Maintainer is compatible with AGM, GEL or WET automotive batteries. Simply plug the unit into your vehicle's OBD-II port, attach the included DeWalt 20V lithium battery pack and you are ready to maintain the charge on your vehicle's battery. LED indicator shows charging status. Also includes a charger for all DeWalt 20 volt batteries. This unit has a Memory Saver function that preserves car settings while charging your car battery for systems such as radio, seats, clock and dashboard settings. Also works with the DeWalt FlexVolt battery on the 20V setting.