The FAMCO FB34 Flat Sub Base 3 inch Tall – No Crimp is designed to give a roof vent three inches of additional clearance for installation on a tile roof. This product features a large flange for easy installation and leak protection. No field trimming required. Weather proof construction. Quality constructed in 28 gauge Galvanized steel. The FAMCO FB34 Flat Sub Base 3 inch Tall – No Crimp comes in a range of sizes: 3¾ inch, 7¾ inch, 9¾ inch, and 11¾ inch. The FAMCO FB34 Flat Sub Base 3 inch Tall – No Crimp is manufactured by FAMCO in the United States and comes with a 1-year warranty against product defects and workmanship. If you have any questions about this product, please refer to the FAQs above or feel free to contact us by phone or email.