Surfboard fins, often over looked when choosing a surfboard as just a thing. The right set of fins can make a surfboard come alive, turn a bad board into a good board, turn a good board into a magic board. FCS has evolved to FCS2, you can still run FCS1 with FCS2 plugs, but not the other way. You will need to add FCS grub screws in to the FCS2 fin plugs or grab the full FCS tab infill kit. Futures use a solid plug and create a stiffer base of the fin.