Overview The Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter lets you connect Thunderbolt and Thunderbolt 2 devices -- such as external hard drives and Thunderbolt docks -- to any of the Thunderbolt 3 (USB-C) ports on your Mac Book Pro. As a bidirectional adapter, it can also connect new Thunderbolt 3 devices to a Mac with a Thunderbolt or Thunderbolt 2 port and mac OS Sierra. In addition, it can be used to connect Thunderbolt-enabled displays -- such as the Apple Thunderbolt Display and LG Thunderbolt 2 displays -- to any of the Thunderbolt 3 (USB-C) ports on your Mac Book Pro. However, using this adapter with an Apple Thunderbolt Display requires a power source, because the display does not provide power through the adapter. Note: This adapter does not support Display Port displays like the Apple LED Cinema Display or third-party Display Port and Mini Display Port displays. What\'s in the Box Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter Tech Specs Thunderbolt 2 Thunderbolt 3 (USB-C) USB C