Here is just over five feet of unused 8" flexible heat duct plus two 8" metal take-off collars. The duct is Grainger part number 3F329 and currently sells on the Grainger site for $2.64 per foot plus shipping. You can find the specs on the Grainger site, just search for 3F329. Also includes two 8" metal take-off collars. Duct and collars have never been used or installed, they are leftovers from a project.
These are located near Jefferson City. You can see them here pretty much anytime, or I can arrange to meet in Helena if our schedules work. Local pickup and cash only ($15.00). Drop me a message through Craigslist if interested, please include a phone number if you would like to discuss by phone.