Description Yster 9″ Straight-line Tracking Flat Water SUP Fin Maximizes directional stability Features The large width of the fin in combination with its angle prevent the pivoting force to rotate the board when paddling, which increases the directional stability. The fin’s angle prevents seaweed from tangling. Fits all Yster’s boards – both hard and inflatable. Fits other boards with Standard Future Fin Box IN THE BOX: 9″ fin. Cover in EVA. Nut and bolt. TECHNICAL SPECIFICATION: Design: Semitransparent fiberglass with tree ring structure.