Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter With the Thunderbolt 3 (USB-C) to Thunderbolt 2 adapter you can use Thunderbolt and Thunderbolt 2 devices - for example external hard drives or Thunderbolt Docks - with any Thunderbolt 3 (USB-C) Connecting your MacBook Pro. The bi-directional adapter can also connect new Thunderbolt 3 devices to a Mac with Thunderbolt or Thunderbolt 2 port and macOS Sierra. It also lets you connect Thunderbolt-compatible displays like the Apple Thunderbolt display and LG Thunderbolt 2 displays to any Thunderbolt 3 (USB-C) port on your MacBook Pro. If you're using the adapter with an Apple Thunderbolt display, you'll need a separate power connector because the display can not draw power through the adapter. Note: This adapter does not support DisplayPort displays such as the Apple LED Cinema Display or DisplayPort and Mini DisplayPort Displays from other manufacturers. For more information, visit the Apple Support page for the Thunderbolt 3 (USB-C) on Thunderbolt 2 adapter.