Layering system for manhole grade adjustment

The Pro-Ring manhole grade adjustment system now comes in square and rectangular shapes to accommodate storm basins and curb inlets. Made from engineered polymer expanded polypropylene (EPP), the system has a 50-year projected design life and meets AASHTO HS-20 and HS-25 loading requirements. The corrosion-resistant material is 1/20th the weight of concrete systems, improving ergonomics and safety for crews. The square model measures 34-by-34 in. on the outside and 24-by-24 in. inside, while the rectangular model measures 36-by-48-in. outside and 24-by-36 in. inside. Both are available in seven thicknesses from 3/4 in. to 4 in., can be layered for precise adjustment, and can be installed with construction adhesive. Sloped versions also available. Cretex Specialty Products. BOOTH #209.