Fiberglass Gully Cover, Pultruded fiberglass reinforced plastic (FRP) embedment curb angle provides a secure and durable seat for grating over concrete trenches and pits. FRP concrete curb angle is a highly corrosion resistant support that provides a strong, flat surface to secure the FRP gratings without additional anchors. Made of fire retardant vinyl ester with excellent corrosion resistance, ideal for concrete drainage ditch, irrigation and structural applications.