The FAMCO GBH B-Vent Pipe Flashing - Adjustable is made for 7-12/12 pitched roofs. The GB is used with a double wall pipe. No field trimming is required. Completely weatherproof. Large flanges. Helps provide proper alignment of pipe. For single wall or "B" gas vent pipe. Quality constructed in Heavy Duty 28 gauge Galvanized steel. The FAMCO GBH B-Vent Pipe Flashing - Adjustable come in a range of size: 3.5 inch, 4.5 inch, 5.5 inch, 6.5 inch, 7.5 inch, 8.5 inch, 9.5 inch, 11 inch, and 13 inch. The FAMCO GBH B-Vent Pipe Flashing - Adjustable 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.