The Severne RAD is the next evolution of the Foil Freek sail.  The smaller sizes of the R4D are very similar to the previous Foil Freek.   Windsurf Foilers love this sail for its light handling and good amount of power.  The Larger sizes from 5.2 and up have a deeper profile for even more power.  If you're looking for an extremely light handling foil sail for your foil board like an Alien or Predator, or if you're working on jibes, duck jibes, 360s or even aerial tricks on the foil, the R4D is for you!  It even works great as a sail for freestyle on the fin!