XL Mystic Marshall kiteboarding seat harness with Stealth Spreader Bar upgrade The Marshall Seat Harness combines strength with maximum freedom of movement, made with premium Flexshell and a 3D moulded backplate, offering optimal back support. The seat cup is pre-shaped, meaning that along with the soft neoprene edges and fix foam, you'll be able to hold down power comfortably and effortlessly while riding