The DQ-4 Quad set is derived from a twin fin keel. Dave essentially split the keels he was using on his twin fins into quads. These are a real fiberglass foiled fin with CFS legs. they will fit into a wide range of fin systems including Fin Solutions & FCS. The  DQ4 Quad fins are designed with an upright profile For sharp turns and tight arcs. they really shine on DQ Quads and the J-lo fun model, but they also can enhance many Quad Boards designed for smaller waves. currently available in Smokey tint