The M-Fins Click Tab Glass Flex fins are compatible with FCSII fins plug, you can put and remove them without tools on the same way as the originals FCSII fins. Tey are made of plastic and fiberglass with a high percentage of fiberglass. As a result, fins are more rigid than others plastic ones.
The side fins are concave which increases adhesion and speed. These fins are ideal for intermediate level surfers. These fins are cheap and the quality is better than regular plastic ones.