We have improved the StompBox™ with the new 9" StompFin™. This fin is designed to help you improve tracking in any deep water without having to compromise your paddling stroke. Collapsing to 3.5", this fin provides incredible drive and control on any waterway while still allowing shallow water river descents. Have you tried ferrying a river with a 9" fin? It's almost effortless. Improve your paddling today with this innovative addition to your StompBox!