The Synergy is part of the 'pro' series by Infinity.
It has a seriously long sleeping time which comes from the concave bearing centering the string and reducing friction.
As with all the 'Pro' series models, the Synergy has a wide string gap and uses a concave bearing and silicon response system. The Synergy also comes fitted with hub stacks which allow you to hold the Yo-yo's sides whilst it's spinning. This opens up a whole new realm of trick possibilities.
Comes with a pack of 5 primo yoyo strings.