GPK Systems&reg; Car Charger for Macbook Pro Md213ll/a Md212ll/a Mc975ll/a Mc976ll/a Md831ll/a 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 power port.