FCS II fin boxes are backwards compatible which means you can use your trusty FCS twin tab fins in your new boards. The FCS II tab infill fit, fills the gaps left in the fin boxes when using older fins. 

• FCS II Tab Infill Kit
• For use with original FCS Dual Tab fins in the FCS II plugs.
• 1 x FCS Key
• 1 x Centre Plug Infill.
• 4 x Side Plug Infills
• 10 x Screws.