The most reasonably priced component used on the Civic 2004 (4) 4dr Dx Side Srs (ka) Duct is the Screw,tapping,(po)4x.
The Duct is made up of components including this Duct Assy,inst which is the most expensive.
A sample from the products for the Duct include: Non Woven Fabric, Seal B(side Def), Seal C, Duct Assy,inst.