... anti-static black flexible1,made of fire-retardant pvc material and helix steel wire2,PVC Thickness:0.35mm-0.65mm3,Diameter:4" to ... acid,alkali,oleic acid, harmful liquid state gas ect. the duct body is without any lapping defect,with the strong points ... .Application :Widely used in these working environment such as tunnel,mining, basement, ship building or welding, laboratory , engine room ,the ...