This fin exploits in miniature the same basic principle that saw Laird Hamilton glide out of the water on his hydrofoil tow board. The wing set perpendicular to the main fin produces lift in the tail of the board in the same way a spoiler creates a down force on the back of a car. The outcome is more glide through flat spots greater control in the wash and plenty of drive and confidence through the turn. Tested by world champ Gary Elkerton this is a single fin designed to replace the middle fin on your thruster setup :: Unisex > Surf Accessories. Good for big wave surfingHelps maintain speed and stability in turbulent waterPc constructionLarge sizeIdeal thruster centre fin Size: one size.