The 85 Watt MagSafe Power Adapter features a magnetic DC connector that ensures your power cable will disconnect if it experiences undue strain and helps prevent fraying or weakening of the cables over time. In addition, the magnetic DC helps guide the plug into the system for a quick and secure connection.When the connection is secure, an LED located at the head of the DC connector will light; an amber light lets you know that your portable is charging, while a green light tells you that you have a full charge. An AC cord is provided with the adapter for maximum cord length, while the AC wall adapter (also provided) gives users an even easier and more compact way to travel.