PVC fabric flexible ducting is made of fiberglass cloth which coated with grey PVC on two sides and steel spiral wire. PVC coated fiberglass fabric is very durable and suitable for flexible installation. Fiberglass fabric is a high strength and fire resistant fabric. When coated with PVC coating on both sides, this coated fiberglass fabric becomes fireproof and waterproof as well. What's more, it is also chemical resistant, abrasion resistant and corrossion resistant.