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|AA-Ring Opening||BB-Seat Dimension||F-Ring Height||Rise||Shape|
|25 1/2||1 1/4||3 1/2||2||Round|
|All dimensions are listed in inches unless otherwise noted.|
Adjusting Rings or extension rings, as they are sometimes called, eliminate the necessity of raising or replacing existing manhole frames on resurfacing projects. The cover recess is
the same depth and diameter as the existing manhole frame. Amount of raise coincides with thickness of resurfacing material, thereby bringing the manhole lid to new position flush with
refinished roadway surfaces.
CAUTION WHEN ORDERING:
Be sure the existing lid diameters are smaller than “AA” dimension in table. The “AA” dimension opening size in extension ring. Lid should measure 1/4″ to 3/8″ less in diameter than this dimension.