FCS Fusion fin boxes are the strongest and easiest fin box to install for twin tab FCS fins. The figure 8 shape spreads provides a stable footprint for optimal strength at the base of the fin and the high density foam-to-foam installation bond ensures the best performance from your fins.
Fusion was developed primarily for EPS/Epoxy surfboards; however the system can be just as easily applied to PU/Poly construction surfboards.
FCS Fusion was designed be installed into the foam before laminating but if you're doing a color pigment lamination it is recommend to route the pocket through the colored fiberglass and cap the boxes with a piece of clear 4 oz fiberglass cloth, then sealcoat the board. The reason to install this way is so you can see the fin boxes and precisely sand the tabs open to keep a clean look.