This 4-inch ducting fits any standard 4-inch inline fan. 

3-layer thickness: Aluminum Foil + PET + Aluminum Foil. 

Helically shaped and internally crimped galvanized steel strip. 

Interlocking steel strips to form an air tight and leak proof system. 

Each ducting unit includes a pair of metal clamps made from stainless steel. 

This air duct is easy to cut using a pair of metal snips or a standard wire cutter.

Have questions? Feel free to contact me via Ebay.

Thanks for looking!