Chimney Roof Jack Flashing. Duravent roof jack for a 7/12 to 12/12 roof pitch. Base is 33” X 37” and is malleable material so it can be formed over a steel roof panel that has ridges, roof jack chimney opening is 10.5”. Brand new, still in box. $50.00. Pics would not upload, but can forward if desired Located in Bath, NH