Zombie - the cave saber opens out in 3 sections to about 41cm to show some "internal workings", it then telescopes shut in one smooth action with a very satisfying "whoosh" from some cleverly built pistons to then be identical to the classic ROTJ saber, in that state it can even be belt hung (not that you ever would !!!!!).
It's a lovely piece of engineering.
From what I've been told , this scene was shot on location and also in the studio for later compositing, but I'm told the footage has been destryed - a terrible shame, but I'm not giving up hope!