It doesn't happen very often, but occasionally I exceed the range capacity of my clamps.
The ones I have the most of are the 40" variety. They seem to cover most of the situations.
The next size up is 50" and I only have 4 of them.
This particular job was over 45" and needed more than that. This is the best use case I have seen for the "Vario" type of the K-body. With a longer clamp, you can move the head down the rail, so you don't have to fit yourself between them to tighten them up.
I have had a few people ask me why I have these and what they do differently, this is it. Bessey also advertises that it can be done for "balance" as in not having the weight of the excess rails pulling against the workpiece.
I have never really had that problem, but this has come up before.
I can honestly say that I probably wouldn't have them if it weren't for the fantastic deal I got, but they have been a great help a few times. Good on Bessey for taking a chance on a fairly limited use item, but I don't think they sell very well, because there is an added cost. Most people won't pay that extra for a rare option's performance, on a chance that they might need it.