I have three sizes of insulated flexible duct. All are in 25 foot lengths in unopened packages. These were over what we needed on a job. The brand name is "Quietflex" and they have an R factor of 6 I have one at 10" 2 at 12" 1 at 14" The outside of them is black. Location: Accokeek it's NOT ok to contact this poster with services or other commercial interests dc