Futures QD2 4.0 HC Quad Rear Fin Pair - Smoke. With an increasing number of quad & 5-fin boards on the market the QD2 is now available in four sizes to suit any rider. Perfect for down the line surfing and fluid rail to rail maneuvers. Featuring a symmetrical foil combined with lightweight Honeycomb, these fins will feel very stable and predictable. Symmetrical foiled rears typically perform better when the boxes are placed closely together.