... 2)Flame retardant vent hose 3)Ducting Semi-Rigid aluminum Flexible Air Ducting for HVAC,ventilation system1.Style No.:BT-50052 ... inside,perfect flexibilityTemperature range:-30°C-+140°C,Max air flow:30m/sMax operation pressure:2500pa.4.Application:Used ... in gigh pressure,low pressure air conditioner and ventilation system,easy installation, graceful apperance,anti- ...