FCS PC-2 Tri Fin Set. Responsive lightweight performance fin designed specifically for groms. Performance Core (PC) material and construction is designed to deliver the feeling of a traditional glass fin with the added performance of reduced weight. The result is a lightweight fin with remarkable flex, a smooth feel and an impressive aesthetic. Base: 4.26" 108.0mm Depth: 4.22" 107.0mm Area: 13.03"² 8405mm² Sweep: 32.3°. FCS.