Alt Tri + Micro Keel Fin Set

The micro keel is designed to provide extra stability and control, specifically in artificial wave pools or river waves where water flow is consistent and fast. It helps lock the board in during turns without sacrificing the speed you get from the standard tri-fin setup.

No, this set is specifically engineered for the FCS II fin system. Please ensure your surfboard is equipped with FCS II boxes before purchasing, as they will not fit standard Futures or older dual-tab systems.

While these fins are optimized for the unique dynamics of river and wave pool environments, they can certainly be used in the ocean. However, they are tuned for high-speed, controlled maneuvers, so they may feel different than a standard thruster setup in variable ocean conditions.

Yes, the set includes the four fins and a fin key. Since they use the FCS II system, you can typically install them tool-free, but the included key is helpful for securing the fins if you prefer a tighter, more permanent fit.

The standard fins have a depth of 4.625 inches, which provides a reliable, predictable hold for most surfers. The 1.695-inch micro keel adds a subtle drag-reducing element that helps maintain speed through turns, making the board feel more responsive in artificial settings.