Pacific Vibrations - Flip Drive
The Flip drive fin was made to bridge the gap between Quads and Thrusters. The Flip Drive adds extra drive and takes out the drift whilst keeping the speed and flow associated with quads. Therefore a boost to drive and control without adding the drag associated with a typical back fin.
With this fin you can also flip it around 180 degrees so the high point of the fin is forward thus moving the pivot point close
 
Dimensions:
Base:  4.5"  (108mm)
Depth: 1.25" (32mm)
Foil: 50/50