An insulated air duct apparatus including insulated duct modules and associated insulated fitting apparatus for transferring a volume of fluid in a warm air heating and air conditioning installation without employing external insulation or structural support members, otherwise required to support and...http://www.google.es/patents/US6231704?utm_source=gb-gplus-sharePatente US6231704 - Apparatus for on-site installation of air duct system
Apparatus for on-site installation of air duct system
