PRO-RING from Cretex Specialty Products is available in square and rectangular shapes for curb inlets and stormwater drainage structures. Manufactured from an engineered polymer expanded polypropylene, these rings meet American Association of State Highway and Transportation Officials HS-25 requirements. Expanded polypropylene is renowned for its exceptional strength-to-weight ratio, chemical resistance, durability and long service life. The unit is approximately 1/20th the weight of concrete grade rings, which makes them safer and easier to handle and reduces the risk of worker injury. The system is designed to eliminate the use of mortar and masonry components, which may deteriorate more rapidly in colder climates from freeze-thaw cycles and snow/ice control chemicals used during the winter. A variety of thicknesses and tapered rings are available, which allows the frame and grate to be precisely adjusted without shimming. 800-345-3764; www.cretexseals.com.