... radius is same as outer diameter Silicone hot air duct for HVAC and ventilation systemMaterial: spring steel wire, glass ... 1.high temperature duct, as suction and blast hose, suitable for hot air , blower, exhausting gas, etc. 2.Heat ... and compressors. -For exhausting gas, engine construction, engine warming, aircraft construction and military construction. Features: 1.Double-layer of silicone coated ...