This compatible Apple 85W charger has the Magsafe 2 magnetic connector which protects the 85W power adapter and the MacBook Pro with Retina display computer. The design of the Mac Magsafe 2 power adapter means that if someone walks past your MacBook Pro while it is plugged into the mains power and kicks your Magsafe 2 mains adapter cable then because it is only connected via a magnetic link it will simply disconnect from your MacBook Pro with Retina display. This will therefore minimize undue strain on both the Magsafe 2 power port and MacBook Pro power cable Compatible Apple 85W mains adapter will charge your MacBook Pro battery while turned on, turned off or in sleep mode. If you have no battery fitted then it will simply power your MacBook Pro. When the Magsafe 2 connector is connected to your Magsafe 2 power port and your plug is switched on an LED located on the top of the DC connector will light up. Amber LED with show you your Mac Pro is charging and when this light turns green you have maximum charge. Compatible with:MacBook Pro with Retina display 85W MacBook Magsafe 2 power adapter specification:Power: 85WInput: 100-240VOutput: 20V 4.25AConnector: Magsafe 2 magneticConnects to: Magsafe 2 power portCondition: Brand new compatibleWarranty: 12mthsModel: A1424, ADP-85FB TIncluded Apple 85W Magsafe 2 power adapter and UK plug