This is a universal click-in fin for stand up paddle boards. Suits board with the US Air fin box - slide fin in and push down to click in place.
The Touring Fin is 9 Inch, the Regular Fin is 8 Inch.
Watch this informative video on how these 'click-in' fins work and how to insert them into your fin box.
Note: These are Bay Sports branded fins, the video below shows the FCS brand however they function in the same way.