The DuraFiber lid is made of resin-infused fiberglass for durability and breaking strengths in excess of 20,000 lb. It fits most ribbed PVC and HDPE riser pipe and weighs 11 lb. Additional benefits of the lid include a flat-style flange, allowing flush-to-grade installation; a cored centering ring, providing an easily aligned, snug fit; and a urethane gasket to help ensure a watertight seal. The lids are available in 24- and 30-in. diameters.