A chimney liner is design to be installed in an existing chimney. Prefab chimneys and masonry chimneys are existing chimneys that can have chimney liner installed in them. A chimney liner is not to be confused with an actual chimney. Masonry chimneys usually have clay flue tiles. These flue tiles can break down over time. Different factors can contribute to this break down. A rigid or flexible stainless steel chimney liner is designed to be inserted in the chimney replacing the function of the clay flue liner.