I think it is a Matthews Reverse Twist...around 3.25" dia.
 
	This Lundberg "Starry, Starry Night" is around 3.2":
 
	(Unfortunately, I have chosen to remove this content due to unchecked behaviors by others on this board.  Moderators may choose to humor it, but I will not.  I don't need to be abused by a Board member while a Mod stands idly by, watching.  My apologies to those who will not benefit from it in the future.)
 
	I have a Ro Purser "Dino Ball" > 3" dia.
 
	IIRC - Mark Matthews produces a few pieces approaching 5".
 
	The Besset piece Photo is just over 3".