... radius is same as outer diameter Silicone hot air duct for HVAC and ventilation systemMaterial: spring steel wire, ... high temperature duct, as suction and blast hose, suitable for hot air , blower, exhausting gas, etc. 2.Heat resistant well ... blast hose, especially suitable: -For transmission hot and cold air. -For printing machines, blowers and compressors. -For exhausting gas, engine construction, ...