The Breather Tube assembly is constructed from several parts from which the Valve Assy,pcv is the most expensive.
In this schematic the "Clamp D 12.5 Tube" is used most often.
Parts such as the Breather Tube: Clamp D 12.5 Tube, Valve Assy,pcv, Washer,plug Drain 14, Tube,pcv are included in the Civic 2003 (3) 3dr Si (ka) Breather Tube parts fiche.