Reinke's exclusive V-Ring seal provides a much stronger flange-to-flange connection that will not allow spans to sag or settle over time. Enclosed inside metal flange to metal flange pipe connections, the V-Ring seal creates no flow restriction in the pipe and is never exposed to the sun, eliminating potential UV damage. Reinke's V-Ring seal can save you thousands of dollars over the life of the system by never having to change them. The V-Ring seal carries a 25-Year Warranty, the longest in the industry.