FCS M Series Glass Flex Tri Fin Set Product Info The FCS M Series Glass Flex Tri Fin Set is designed to deliver speed, smooth flow, and reliable hold with added “squirt” through turns. Featuring inside foil technology (IFT), these fins generate superior drive, while the flexible tip provides forgiveness and control at higher speeds. Glass Flex construction is engineered to replicate the flex and memory of hand-layered fiberglass. Compared to traditional composite fins, it offers increased stiffness, a more controlled flex pattern (with responsive tip flex and minimal base flex), and excellent flex memory for consistent performance. Manufactured using a precision injection molding process, each fin is produced with exact geometry for dependable, repeatable performance. Fin Size Details Size Base Depth Area Sweep Foil Rider Weight M-3 Small 4.28" 4.41" 14.22 in² 31° IFT Under 120 lbs M-5 Medium 4.37" 4.55" 14.76 in² 33° IFT 145–175 lbs M-7 Large 4.52" 4.67" 15.71 in² 33° IFT 165–200 lbs
