Flexible vinyl woven polyester with a carbon wire spring and adhesive tape, applied hard-wearing, smooth interior wall. Extremely flexible and flame-resistant design. Free large bag for convenient duct storage and transportation. It takes very little effort to collapse the retractable duct and repack it within the bag. Simple to connect to the extraction side fan lip and to install. Rings are practical and long-lasting thanks to the reinforced design, which includes thicker high carbon wire spring and wear-resistant professional industrial adhesive tape.