Thunderbolt 3 to Thunderbolt 2 Adapter

The Thunderbolt 3 to Thunderbolt 2 Adapter is an adapter dongle from Apple.

Usage
The adapter allows newer Macs with a Thunderbolt 3 or USB4 ports to be connected with older Thunderbolt 1 or 2 devices. The adapter is bi-directional and can also allow older Macs with Thunderbolt 1 or 2 ports to be connected with Thunderbolt 3 and USB4 devices, but at lower speeds.

The adapter does not carry through power for peripherals such as the Apple Thunderbolt Display, which would require a separate power supply. It also does not support Mini DisplayPort signals, which would require a 3rd-party adapter.