The FAMCO ATASS Tile Cap Adapter allows a square chimney tile or flue to accept round caps to terminations. The adapter fits over masonry and tile chimneys. This product includes a draw bolt collar for easy installation and a secure fit. Quality constructed in 28 gauge Stainless steel. The FAMCO ATASS Tile Cap Adapter is a custom item requiring your exact length and width measurements for the outside dimensions of your flue. The overall height of the adapter is 3½". Make sure to take accurate measurements to ensure ordering the correct size. We are unable to make an adapter for flues larger than 14" x 18" rectangular or 16" x 16" square. The FAMCO ATASS Tile Adapter is manufactured by FAMCO in the United States and comes with a 1-year warranty against product defects and workmanship. Please note that this adapter is built custom sized to fit your flue, and is not eligible to be returned for a refund. If you have any questions about this adapter, please refer to the FAQs above or feel free to contact us.