Dérives FCS II MARK RICHARDS NEO GLASS ECO TWIN + 1FCS offers its brand new range of "ecoblend" fins composed of a 50% biosourced resin and fiberglass. The Mark Richards Twin + 1 model in Neo glass eco construction offers exceptional pivoting while the central fin (the stabilizing fin) adds control while retaining the spirit of the twin. This model works equally well for fish, scalable and twin fin.