Endorfins KS1 Single Tab Tri-Quad Fin SetA 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. The FCS II compatible base will require two screws that will come with the fins. Endorfins with FCS II compatible bases will not click in and click out. Designed by 11 time world champ "Kelly Slater" Fin Size Details