I searched and took a closer look. The width can be extended by adding more vices and mounting them next to each other. Titanium seems to be a separate option to stainless if you need portable. Then it makes more sense.
A more general question popped up in my head about the use of such vises - if you need place an object precisely, or do a series of objects placed exactly in the same place, these vises seem to lack any obvious reference planes or holes to ease precise or repeated placement?
(On a sidenote - if you have some really difficult stuff to hold, which can take a bit of temperature, then there are special low melting point metal alloys made for exactly that. Melt, pour around what you need to hold forming a clampable shape overall, then and melt away again when you are done).