Thanks for your answers my friends.
Hollow tubes existed back then but the solid rod was preferred for strength and mass.[...]
Maybe but 5 g more for this SUL and a hollow carbon Upper Spreader is stiffer than a solid carbon rod.
BTW, if you check your upper LE, it should be Skinny SUL, not UL.
I knew that Doug, thanks. And what about the spine ? I have read Skinny UL and Skinny S
UL too ?