Pultruded fiberglass gratings are based upon I-beams, T-bar etc, in load-bearing direction, which are connected by rods and distance tubes. They are glued together torsion-free. Standard FRP/GRP pultruded gratings are made from isophthalic polyester resin. The reinforcement is achieved by a combination of fibreglass mats and rovings reaching a glass content of approximately 65%. Standard colours are grey or yellow, other colours according to RAL are available.