Designed with FCS's Neo Glass material, the FCS Reactor Neo Glass Surfboard Fins are lightweight, stiff, and extremely responsive, working best on hollow waves and short, punchy beach breaks. Extremely fast reacting, the Neo Glass Fins are ideally suited for surfers who stay tight in the pocket, helping them perform quick changes in direction, tight radius turns, and aerial maneuvers. These fins are only compatible with the FCS II Fin System. Additionally, the fins' optimum weight range is 145 to 175 pounds. Pair them with the FCS II Quad Rear fins not included for quad and quadtri fin set ups.