The square and rectangular Pro-Ring is manufactured from the same engineered polymer, expanded polypropylene (EPP), as the round versions and meets the loading requirements of AASHTO HS-25. EPP is renowned for its exceptional strength to weight ratio, chemical resistance, durability and long service life. Pro-Ring is approximately 1/20th the weight of concrete grade rings, which makes them easier to handle, safer and reduces the risk of worker injury.
