Foster supply stocks concrete and HDPE grade rings
to meet project requirements. Concrete grade rings are available in the following heights. 2", 4", 6" and 12". Foster supply has 1.25", 1.5" and 2" HDPE grade rings in stock for projects where light weight, rapid installation and noncorrosive properties are important. They are also provided in variable thickness to make up for grade differential when manholes are placed on sloped terrain.