evo.com | Captain Fin Fins > Designed by Alex Knost, the Captain Fin Alex Knost Flex 10.0 Longboard Fin features a medium flex, wide base, and 10" height, for a smooth, sweeping ride. 1 Fin Medium Flex Designed by Alex Knost Fiberglass and Resin Compatibility Works best on pintail and squaretail logs. | Captain Fin Alex Knost Flex 10.0" Longboard Fin 2024 - 10 in Blue