Abstract: First and second members are provided and include central registered openings formed therethrough. The first and second members are positionable on opposite sides of a panel having a vent opening formed therethrough of a size and shape complementary to and registered with the openings in the first and second members. Connecting structure is connected between the members securing the latter together for frictionally gripping the panel therebetween and the first member defines a tubular member and includes a cup-shaped cover having closed and open ends supported therefrom in position loosely embracing the end of the tubular member remote from the second member.