PVC flexible duct PVC hose, flexible hose PVC flexible duct Flexible duct is made of fire-retardant PVC material, spring steel ring , rope and metal ring , can ... acid and alkali-resistance, small ventilation resistance, small ventilation noise, easy installation, high leak tightness.,1)Material: PVC tarpaulin 2)Thickness: 0.35mm ... bag and carton. 5) MOQ: 10 pieces per specification PVC flexible duct