GPK Systems&reg; Car Charger for Macbook Pro 13.3-inch 15.4-inch Laptop with Retina Display 85w Power Adapter Input: DC 11V - 16V Output: 20V 4.25A 85Watt LED indicator shows you when your computer is charging and when it is fully charged Compatible only with Macbook Pro 13- Or 15-inch featuring MagSafe2 power port. Connector: MagSafe2