PRO-ring is the worlds first and only manhole grade adjustment system made from Expanded Polypropylene (EPP), the same engineered polymer material that has been used in the automotive industry since the 1980's. This high strength, lightweight plastic is the ideal material to replace traditional construction methods which use concrete, mortar and other masonry materials to raise manhole frames to their final elevation. These masonry materials deteriorate rapidly over time due to the runoff of road salts, freeze-thaw, sewer gases and from continuous traffic impacts. The PRO-ring system dramatically reduces the time and equipment required to construct or reconstruct a single manhole adjustment. Manhole repair sites can be opened and closed in a single day or in a few hours depending on pavement type and site conditions. This results in significant savings and minimizes the impact on traffic when it is necessary to close traffic lanes or streets to complete the work. The PRO-ring system is installed and assembled using a polyether-based adhesive/sealant which is applied using a caulk dispenser. This adhesive/sealant material has proven to be effective at sealing and bonding the rings to the manhole cone and to each other. The use of the PRO-ring system may result in as much as a 20% to 30% overall savings when considering the expected 50 years Design Life. The PRO-ring system is also backed by an industry leading 25 years material warranty.