BIC SUP fins are made of highly durable polycarbonate. The center fin box in all BIC SUP boards is a 10” Universal Fin box and will accept any longboard style fin. The fin(s) included with BIC SUP boards are designed to optimize performance, however other fins can be used to customize a boards performance. In general shorter fins are more maneuverable but less stable, while longer fins will offer better tracking and added stability. Side fin boxes are included on certain BIC SUP models and are recommended for surfing conditions where added ‘hold’ in the wave is needed. We recommend only using the center fin for general flat-water paddling and touring.