Designed for mid-length fish surfboards, these quad keel fins are compatible with Futures fin boxes. Beyond their unique quad performance, these fins offer a balanced speed and turn performance, characteristic of keel fins. Widening the base of the fins enhances elongation (drive ability) during turns, while the strong sweep allows for larger turns compared to general quad fins. Compatible with fish boards, they enable a stretched turn experience. In addition to nanazero surfboards, they also fit surfboards with Futures fin boxes. *Please ensure to check the specifications before placing your order. *This set includes 4 pieces for the front, back, left, and right. Install them with the logo side facing outward.