The Innegra Parabolic Rail works as a stringer around the whole shape, adding extra stiffness to the board. To ensure the best stiffness ratio, the rail is fully covered with Innegra, a high modulus polypropylene fiber that has excellent impact resistance. The parabolic form of the rail combined with the molded fibre creates a strong and solid U-beam structure that connects the deck, rail and bottom. Innegra is pigmented instead of fully painted to save weight and avoid paint chipping.