ZOTAC is claiming bragging rights about the size of their new GTX 1080 Ti's, that they are the smallest of their kind. The two new cards measure a miniscule 210.8mm (8.3") in length and in the case of the Arctic Storm mini it is the lightest watercooled GPU on the market.
You can see the size of the ZOTAC GeForce GTX 1080 Ti Mini by how much of the length is taken up by the PCIe connector, compared to most 1080 Ti's which are over a foot long. This card is not long enough to fit a third fan on.
The Arctic Storm version is the same size as the air-cooled model but opts for the worlds lightest watercooler. That may mean you want a powerful pump attached to the GPU as there is less metal to transfer heat but it means small silent builds can pack a lot of graphical power.
Both these cards will use dual 8-pin PCIe power connectors, expect to see more of them at Computex.