The Predl Base Liner is an inextricable component of a liner solution for new manhole construction. Many benefits from Predl Manhole Liners are available; the one-piece molded Base Liner alone provides many of the advantages available from a lined manhole structure. These benefits include: precise custom and standard flow channels, integrated pipe-specific watertight Bells and the manhole wall lined up to the first riser joint. For a Complete System the liner solution may be extended further to include Wall Liners for all riser sections and either Concentric or Eccentric cones or a Flat Slab Top with a watertight Telescopic Access Collar at road elevation. In addition, Predl offers a compact, cost-effective Inside Drop fitting to accommodate gravity-fed sewage lines with elevation differences between manholes that are 24” (610mm) or greater. To manage and control channel flow, Predl distributes Slide and Flap Gate Valves from leading industry suppliers. Safe, cost-effective ladder rungs with inserts securely embedded in the concrete manhole structure are also available.