Santa Barbara Surfing SBS - 8 inch Longboard & SUP Single Fin - 8" Center Fin for Surfboard & Paddleboard PERFECT REPLACEMENT FIN: This fin is a direct replacement for many off the rack SUPs and longboards. Upgrade to our 9" or 10" fins for even greater hold and drive. SPECIFICATIONS: Glass Filled Nylon makes this hard plastic fin strong. COMPATIBILITY: Works on any SUP or surfboard with a standard 8.5" or 10.5" fin box. KNOWN INCOMPATIBILITIES: Some Inflatable SUPs such as the Bali Solstice, AquaMarine SPK2, see our compatibility image for more. INCREDIBLY VERSATILE: Suitable for Longboard / Surfboard / Stand Up Paddle FREE "NO TOOL" FIN SCREW: We include our No Tool fin screw and plate set so you can install this on your board right away without any tools.