Apple 85W MagSafe Power Adapter (for 15- and 17-inch MacBook Pro)MC556ZM/B Use an extra adapter for home or work. Apple's innovative AC adapter is made specifically for your 15- or 17-inch MacBook Pro. 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. Designed to be the perfect traveling companion, the adapter has a clever design which allows the DC 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 with 15- or 17-inch MacBook Pro.