They haven't given us much detail but as you would expect the ZOTAC external GPU box connects an GPU to your system via a Thunderbolt 3 connector, allowing you to add more GPU power to a mobile system or any other computer which needs a little boost to its graphics.  You can fit cards of up to 9" in length, which makes it a perfect match for the two Mini-GPUs just below or other lower powered cards which are not as well endowed as your average GTX 1080 or 1080 Ti.  It also adds four USB 3.0 ports and a Quick Charge 3.0 port to your system so you can leave it at home and simply attach your laptop via the Thunderbolt cable and get right to gaming.