The 85W MagSafe Power Adapter is a direct replacement to the charger supplied with your 15″ or 17″ MacBook Pro.Designed to prevent unnecessary damage by disconnecting itself if it experiences undue strain, the Apple 85W MagSafe Power Adapter also features an LED to indicate when your computer is charging and when it is fully charged.The Apple 85W MagSafe Power Adapter is extremely portable, making it the ideal travelling companion for your MacBook Pro.