Dorsal Surfboard Fins FlexCore Surfboard Quad Set (4) FUT Base - Natural FlexCORE Quad Surfboard Fins Set - Natural These glass filled fins with futures compatible base suit performance short boards fish and more. Symmetrical GL style rear fins create smoother rail-to-rail transitions in a variety of conditions. Rear fins are asymmetrical side foils (as opposed to center foils) for tighter arcs and pocket surfing. FlexCORE is the DORSAL material formulation created to capture the slight flex and memory properties of laminated fiberglass in a fin that is manufactured using injection molding techniques. By using injection molding DORSAL can create complex templates with precision and ensure consistent quality in every fin. Its also least expensive way to manufacture fins so the prices reflect that. These sizes cater for all surfers in all round conditions. Front: Base: 4.28in. Depth: 4.41in. Area: 14.22sq.in. Rear: Base: 3.86in. Depth: 3.93in. Area: 11.07sq.in.