DeWalt DW9109 XR2 Car Charger One Hour Charger Charges from vehicles cigarette lighter outlet enabling batteries to be charged while driving to work or on a jobsite without power Charges all DEWALT 7.2V to 18V batteries (except Univolt batteries) so users need only one charger for multiple cordless tools Automatic shut-off protects excessive discharge of vehicles battery Patented voltage booster circuitry charges whether vehicle motor is running or not for more flexible use and convenience for reduced downtime Circuitry boosts input voltage to allow recharging one battery after another to save time and improve productivity