mugatu, the blade is perfectly round with no flattened edges. Its also not motorised as the flat blades were but it should be remembered that this is only one of the variations from New Hope and I suspect, the last version used as a training blade. The blade is very long (longer than seen in the movie IMO) and its covered by 3M reflective tape that still works perfectly when shot with a camera flash - as you can see from the screengrab.
Deltaflyer90, in answer to your question, I originally thought that they were made out of a fibreglass similar to the antenna we used to have on our armoured vehicles in the army but they flex too much and the tape would have come off after a single fight. Looking at the blade on this saber I would guess that its a wooden rod, rounded at the end, coated in 3M tape and embedded in the hilt because the heft is just right IMO, not too heavy and not too light. Here is a grab of it without the flash.
View attachment 468136
My apologies that I can't show the actual photographs..
Regards
MARK