FCS II Christenson Performance Glass Twin FinsThe Christenson Twin Fin set provides smooth and fast down the line speed. Overview From high performance twins to more traditional shapes, this is a perfect compliment to your twin fin. This set provides smooth and fast down the line speed. Board Types Designed to fit the FCS II Fin System. Recommended for all board types including fish, funboard and twin fin boards. Performance Glass Performance Glass (PG) fins are machine cut from layers of solid