The idea of transforming the Butterfly into aluminum is a pretty bold concept. The original Butterfly design is really something you don?t want to mess around with. After a lot of thought, we finally decided to design something aimed towards modern responsive yo-yoing; maintaining the feel of the original Butterfly but gearing the yo-yo towards a trickset that wasn?t invented at the time of the original Butterfly?s release. Our goal became to keep that timeless Duncan feeling, to make the yo-yo play responsively without sacrificing performance, and, of course, to keep the look of the Butterfly AL as close to that of the original Butterfly as possible. This Yo-Yo is reponsive. Default bearing is size c. For narrower gap, use half spec bearing size c.