The Apple Thunderbolt to Gigabit Ethernet Adapter lets you easily connect your MacBook Air or MacBook Pro with Retina display to a high-performance Gigabit Ethernet network. Small and compact, it connects to the Thunderbolt port on your Mac computer and provides an RJ-45 port that supports 10/100/1000BASE-T networks.

Requires a Mac with a Thunderbolt port running OS X v10.7.4 or later.
What's in the BoxApple Thunderbolt to Gigabit Ethernet Adapter with built-in Thunderbolt cable