The 45-Watt Mag Safe Power Adapter for Mac Book Air features a magnetic D C connector that ensures your power cable will disconnect if it experiences undue strain and helps prevent frayinGOr weakeninGOf the cables over time. In addition, the magnetic D C helps guide the plug into the system for a quick and secure connection. When the connection is secure, an L E D located at the head of the D C 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 A C cord is provided with the adapter for maximum cord length, while the A C wall adapter (also provided) gives users an even easier and more compact way to travel. Redesigned specifically for Mac Book Air, the adapter is the perfect traveling companion. It has a clever design which allows the D C cable to be wound neatly around itself for easy cable storage. This power adapter recharges the lithium polymer battery while the system is off, on, or in sleep mode. It also powers the system if you choose to operate without a battery. Compatible only with Mac Book Air with Mag Safe Power Port. Apple Type Adapter In the Box Apple 45 W Mag Safe 2 Power Adapter System Requirements Compatible with Mac computers with Mini Display Port and Thunderbolt ports Color White In the Box Apple 45 W Mag Safe 2 Power Adapter U P C-A 885909530038