Rockford Chimney Supply RockFlex Stainless Steel Smooth Wall Chimney Liner Tee Kit, 6 Inch x 25 Feet Complete Do It Yourself installation instructions; We will support you before and after the sale RockFlex Chimney Liner Warranty; The only warranty that is transferable to the next homeowner UL1777 Listed in the USA and ULCS635 in Canada; Flexible liners are only to be installed inside a masonry chimney Quick Connect System; Simply tighten the clamps and enjoy your UL listed RockFlex liner Superior flexibility; Increased BTU capacity; Smooth interior design allows for more airflow