Product features: 1, internal and external screw steel wire fixed, so that the insulation material is evenly coated on the inner tube; hose bending, will not cause the thermal insulation cotton bag and cracking phenomenon. 2, hose, cotton insulation, plastic outer hose to achieve the best effect of heat preservation all blend into one harmonious whole. 3, inner and outer spiral wire support, improve the strength of the hose; hose bending, creasing uniform and beautiful. Scope of application: the central air conditioning and ventilation system includes humid environment, slightly corrosive environment (such as marine climate) and complex installation environment (in favor of finished product protection). Product features: the mechanism of the integration of the winding jacket, no longitudinal joints, thermal insulation, jacket without cracking, glass fiber filament winding to strengthen, prevent tearing. Range of specifications (diameter): 52 ~ phi phi 559mm Temperature range: -30 ~ +140 Maximum air flow rate: 30m/s Maximum working pressure: 3000pa Bending radius: 0.54*d+25mm Centrifugal glass wool thickness: 25mm Centrifugal glass wool density: 20 ~ 24kg/m3 Fire performance: b1 level (hard to burn)