The SK Fiber Hypersonic is a lightweight shaft to enable the golfer to maximize clubhead speed and distance. But where the Hypersonic shines is that fact that they are counterbalanced.
Normally only found in more expensive shafts, counterbalancing allows for a couple different advantages: 1) More weight in the hands has resulted in more consistent shotmaking and distance for some players (hence the popularity of butt counterweights). 2) You can build longer clubs to have a more comfortable swingweight if swingweight is something that concerns you.