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) / USB 4 ports on your Mac. As a bidirectional adapter, it can also connect new Thunderbolt 3 devices to a Mac with a Thunderbolt or Thunderbolt 2 port and macOS Sierra or later. 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) / USB 4 ports on your Mac. 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 DisplayPort displays like the Apple LED Cinema Display or third-party DisplayPort and Mini DisplayPort displays.