The FCS II Reactor GF Thruster Surfboard Fin is a high performance surf fin made from Glass Flex material. The FCS II Reactor GF Thruster Surfboard Fin is recommended for performance shortboards with moderate-to-low rocker and surfed in hollow, fast, waves and punchy beach breaks. A more advanced fin the FCS II Reactor GF Thruster uses an upright template with flat foils on the side fins to allow for acute directional changes. In other words the FCS II Reactor GF Thruster is designed for surfers who like to stay tight in the pocket and perform tight, quick turns, and aerial maneuvers. *Please Note: this fin is designed to be used exclusively with the FCS II Fin System, and will not fit in the traditional FCS Dual Plug System.