Abstract: An adapter system for vehicle windshield defroster including a manifold assembly including at least one manifold member having a defroster interface aperture formed through a bottom surface thereof that is surrounded on an outer bottom surface of the manifold member by a resilient gasket member secured to the outer bottom surface and a magnetic member secured to the gasket member, a manifold chamber formed within the manifold member in air flow communication with the defroster interface aperture, and at least one diffuser bar aperture that is in airflow communication with the manifold chamber; and at least one elongated diffuser bar having an airflow passageway formed along the length thereof, an air inlet aperture formed at a first end thereof in airflow communication with the airflow passageway, the first end of the diffuser bar being adapted to seat within the diffuser bar aperture in a manner to establish airflow between the airflow passageway and the manifold chamber, and a plurality of spaced diffuser a