Product Details  Insulated PVC & Alum Flex combined Duct covered by fiberglass insulation and aluminum jacket and with PVC & aluminum core  Insulated PVC & Alum Flex combined Duct covered by fiberglass insulation and aluminum jacket and with PVC & aluminum core Good insulation---heat insulated. No corrosive---not corrode the alu. pipe and metal parts. Durability---not decay, mildew, durability. Fire---resistance. Practicality: suitable for the densely-populated area (such as school, supermarket, office, stadium, theater, factory...) high requietment of the enviroment area, such as hospital, laboratory, howff, bus, train, broadcasting studio. PROPERTIESVALUEDiameter Range80-750mm (3"-30")Temperature Range-30 ~ +140ºCVelocity Of Air Flow (MAX.)30 m/sWorking Pressure2500 PaBending Radius0.54*D+25MMThickness Of Fiberglass Insulation25MMDensity Of Fiberglass Insulation16~32KG/M3Standard Length10M,5M etc NOTE: OTHER SIZES AND LENGHT ETC ARE AVAILABLE ON REQUEST.