One fusion center plug for the FCS fins. Also known sometimes as dual tab fins.
A fusion plug gives greater strength and hold into the structure of the surfboard. If you want to buy a complete thruster setup you have to buy 1 center plug and 1 rail plug set. For a quad setup you buy 2 rail plug sets. For a 5-fin setup you buy 1 center plug set and 2 rail plug sets.
Small color accents might be used to indicate the difference between 0, 3, 5, and 9 degrees. These colors are often not visible on the product photos. All plugs come WITHOUT screws.
Buy Fusion Center Plug set (1 plug) - Longboards, Funboards, Fins & Surf Leashes @Billy.be: Your Expert in Watersports