The Grade N Seal system from Terre Hill Concrete Products is the total solution for manhole to frame riser installations. The 4-way seal of Grade N Seal assures a vacuum-proof seal and eliminates inflow of wastewater and runoff into sanitary and storm water systems. Laboratory tests prove that Grade N Seal is stronger than concrete, brick and mortar and can withstand extreme stress conditions.
Grade N Seal is ideal for both new construction
and rehabilitation work. Each Grade N Seal kit contains all the
necessary material for a fast and easy installation. That eliminates
the need for ordering separate grade rings, mortar and sealant.
All threaded rods, washers and nuts are included in each kit. Grade
N Seal's lightweight design requires no heavy equipment, mortar
mixing or stocking inventory of grade rings. 
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