ANY adapters for using USB-C devices on Mac Pro (2013)?

Hi there, can anybody help me?
Now the new MacBook Pro is out all these great USB-C SSDs come out and mark a new speed gain. But they only run USB-C! And I was searching the whole weekend for an adapter but I haven't found one!
Is there at least one solution for Thunderbolt 2 users to connect to a USB-C device with at least TB2 speed?

Thank you

Did you check Apple's online store?

www.apple.com/shop/product/MMEL2AM/A/thu...b0%252B309a%252B44c3

Yes I did but isn't this cable only being used for connecting USB-C hosts to older devices?

UPDATE: Oh now I understand: support.apple.com/de-de/HT207266 this helped a lot!
So maybe I want to use a SanDisk Extreme 900 with my Mac Pro (2013) I have to buy a powered USB-C dock which supplies the SSD with power because the adapter doesn't support powering from TB2 to TB3. Right?

Oh, you want a bus powered drive?

YEAH, because the SanDisk Extreme 900 is really fast for editing 4K stuff and has 2 TB of space. But it is bus powered and so not compatible with Apples own adapter. So must it be an USB-C hub/dock which has it's own power supply to be compatible with the Mac Pro?

Or is there any other external drive with that space+speed+price point?