Because not every day calls for a high-performance thruster, this modern take on a classic keel fin will have you feeling all sorts of good on your twinnie. It features a lower sweep (or rake) than most keel fins (allowing it to pivot more easily), while the higher surface area provides control during harder turns on open faces.Designed to fit the FCS II Fin System ad recommended for all board types from fishes and twin fins to fun shapes.