Feature:1. The fin will increase the driving force and provide directional control by turning without sacrificing the speed, flow, or freedom of movement normally associated with the quadrilateral.2. A single tongue is designed to position the fins on the front and rear central plugs to meet the individual drive requirements of each surfer.3. When used with a flat head screw and FCS filling kit, it will fit the FCS II fin system.4. Simple to attach and to remove.5. Great accessory for kayaks, canoes and rowing boats.Specification:Condition: 100% Brand NewItem Type: Tail Fin Material: Glass fiber, unsaturated resinColor: blue, black, red (optional)Fin size: 10.3x4.5x0.6cm/4.1x1.8x0.2inchSlot size: 2x1.3x0.6cm/0.8x0.5x0.2inchBase: FCS baseUses: surfboard, paddle board, kite board, air board, etcPackage List:1 x Tail Fin