Here's another HomeSaver industry innovation - RectangleFlex.
Before RectangleFlex, the whole family of 7" X 11" flues into which 8" stoves were vented could not be relined without downsizing - because you obviously can't get 8" round relining pipe down a 7" X 11" flue. and downsizing goes against NFPA 211 code. Then Rectangleflex came to the rescue.
*Click here for Flexible Liner installation diagrams.