Endorfins Slater KS Twin Futures Twin+2 Surfboard Fins - BlueDesigned by 11 time world champ "Kelly Slater" KS Twin 2 +1 A better build innovative carbon inlays in Endorfins add strength and flex that enable them to be built with a core comprised of 90% pure air. As a result, Endorfins not only provide optimum performance but also literally float on water. This set includes a 2" and 1" 'nubster' trailer fins. FIN BOXES: Each set is built with a base that is compatible with either TWO TAB FIN BOXES or SINGLE TAB