I purchased this to offload media files from a Dell Precision 7760 via its TB4 port through this adapter to a G-Raid storage system with TB2 ports. Both source and destination systems function properly with other devices. I would be happy with 15 Gbps transfer rate. Put this Apple converter in and go out for a drink... dinner... movie and a trip to the other end of the world before the file transfer at 20 Mbps completes.

Over the decades, Apple has attempted to set the standard for high-speed peripheral connections, only to have the universal serial bus, USB, overtake them. Firewire 800 was great, but it seems pokey compared to USB 3.0. Thunderbolt 2 was conceived as a better way to connect hard drives and other peripherals using the same type of interconnect as their displays of the era. It was designed as a superset of the mini displayport and at 20 GHz, much faster than any flavor of USB, making it ideal for connecting RAID storage devices and the like. However with USB 3.0 type C Gen 2, USB has again caught up and is poised to surpass the older Thunderbolt 2 connection standard.Thunderbolt 3 is finally a step in the right direction, merging the Thunderbolt and USB type ... MoreOver the decades, Apple has attempted to set the standard for high-speed peripheral connections, only to have the universal serial bus, USB, overtake them. Firewire 800 was great, but it seems pokey compared to USB 3.0. Thunderbolt 2 was conceived as a better way to connect hard drives and other peripherals using the same type of interconnect as their displays of the era. It was designed as a superset of the mini displayport and at 20 GHz, much faster than any flavor of USB, making it ideal for connecting RAID storage devices and the like. However with USB 3.0 type C Gen 2, USB has again caught up and is poised to surpass the older Thunderbolt 2 connection standard.Thunderbolt 3 is finally a step in the right direction, merging the Thunderbolt and USB type connection standards, Apple now has a clear path forward that will resolve the issue of standards for the foreseeable future. Unfortunately, if you have an older Thunderbolt 2 device that costs several hundred or thousand dollars, you're probably not ready to retire it, just because you got a new computer. This adapter solves the problem, allowing you to connect Thunderbolt 2 devices to Thunderbolt 3 ports and even to USB type C ports.There are some caveats, however. Firstly, this adapter is rather expensive, but there's a reason for that, as it contains a working Thunderbolt 2 driver chip. This adapter is not to be confused with inexpensive USB C to mini displayport adapters, that are very common. Those do not include the Thunderbolt 2 chip and they are not bi-directional. They're designed for output to a display only and will not work with Thunderbolt 2 devices. With only a few other adapters on the market, the Apple adapter is really the only game in town, which is unfortunate, as it has some major shortcomings.Secondly, there is no power pass-through. That means this adapter cannot be used with a bus-powered device. Transcend makes an outstanding Thunderbolt 2 portable SSD, but it won't work with this adapter because it derives it's power from the Thunderbolt 2 connection. Fortunately, it's still possible to daisy-chain Thunderbolt 2 devices, so one can still use a bus-powered device, provided an externally-powered device such as a RAID enclosure is placed between the Apple adapter and the terminating device.Finally, the Thunderbolt 2 connection itself is not all that robust and even a small amount of movement can disrupt the flow of data and cause the dreaded "disk not ejected properly" error message. One cannot help but wonder why Apple chose to use a dongle for such an unstable connection, as dongles frequently are associated with movement. If this adpater is used with a cable that regularly moves, I would strongly recommend tying the cable down to an item that doesn't move, so that the Thunderbolt 2 connection is isolated and remains stationary. Otherwise, interruptions in data flow with resulting data corruption are to be expected.In summary, the Apple Thunderbolt 3 to Thunderbolt 2 adapter is an essential device when connecting older Thunderbolt 2 legacy devices to a newer computer that lacks a Thunderbolt 2 port. Just don't expect to draw power through the adapter, and don't expect it to tolerate any movement at all at the Thunderbolt 2 connection interface.

If you need this, you are probably wanting to do something that Apple does not want you to do. They would rather you buy new equipment and not try and make your legacy equipment work. Sometimes Apple literally blocks the drivers of third party manufacturers so that it won't work. For example, I've had equipment not work at all with this, but it shows up as a connection in System Report, so the connection DOES work, Apple just blocks it. Just beware that even though this seems like it should solve your problem, it might not.