LADTECH manhole riser rings make the chimney riser section of the manhole uniform and completely watertight. Made from 100 percent recycled HDPE and sealed with butyl rubber sealant, the joints between the cone, risers, and the frame and cover are permanently flexible and watertight. Their H25 Traffic Load rating also ensures that traffic impact will not compromise the performance of a system, keeping it intact and eliminating one of the major sources in systemwide I&I. The rings are impervious to hydrogen sulfide gasses and include slope rings and rings as small as 1/4 inch, allowing for a precision installation. 877-235-7464; www.ladtech.com.