pvc sprial wire and sewn flexible duct

pvc sprial wire and sewn flexible duct
A strong, durable, lightweight sewn ducting product. Used time is longer. Is both portable, flexible, compressible and retractable down to 1/7th of its fully extended length  depending on the pitch and fabric selected.  The encased steel-wire helix construction prevents collapsing and crushing of the duct, while remaining resistant to abrasion, fatigue and deterioration from weather and chemical influences. 

character:
1.fire-retardant PVC material ,helix steel wire and both sides sewing in strip
2.The both ends with the black sleeve and buckle
3.durable and use longer