FCS created the Fusion because of a need for a high quality, easy to install system, that can be installed under the fiberglass (as preferred by boards using new technologies such as EPS). This also provides the consumer a higher performing fin system that fits the worlds largest range of premium fins.
Rail Plug 5 degrees. The insert provides a base of high density foam. This helps disperse any forces on the plug. It provides a solid base so the plug does not rotate or sink into the foam. This is especially evident in EPS blanks of low densities.
The slots in the Fusion plugs are slightly elongated which allows slight fore and aft movement of the fins, this is great for fine tuning the performance of the board.