FCS II Carver Glass Flex Tri Surfboard Fins - Large/BlackThe FCS II Carver Surfboard Tri Fin Set. Find Power. Powerful, drawn out turns with added hold. Ideal Conditions: Open face, down the line waves, particularly good in point and reef breaks. Board Types: Designed to fit the FCS II Fin System. Recommended for boards with deep concaves and moderate to extreme rocker. Features Designed for powerful, drawn out turns with added hold. Elongated template with high degree of sweep provides exceptional hold off