Since 1989, Strong has developed specialized cementitious products and patented application equipment to provide a variety of manhole rehabilitation solutions. By providing a total system-engineered products, specialized equipment, and complete customer service Strong-Seal® remains the technology leader in manhole rehabilitation. Extensive research and development activities, on-going laboratory testing, and nationwide service are just a few of the advantages that make the Strong-Seal® system unique in the industry and the best solution for rehabilitating municipal sewer structures.