Single material, like PET, MPET, PVC and Alu tape, could be used to make flexible air duct. The regular size is as below:
PET: 0.012-0.03mm
MPET: 0.012-0.03 mm
PVC: 0.06-0.1mm
Alu tape(semi):0.05-0.12mm
Single layer air duct is the ideal choice for venting industry.