Abstract: A self-stabilizing extrusion for closure assemblies, including awnings, canopies, and displays having an elongated hollow frame substantially rectangular in vertical cross-section with inside and outside surfaces which is constructed of a top wall perpendicularly connected to parallel side walls terminating in perpendicular flange members parallel to the top wall. A slot opening is formed between the flange members for the receipt of closure material. The side walls are also interconnected by a slot base to which the closure material is affixed. A base support is provided between the slot base and the inside surface of the top wall. The slot is defined by the slot opening, the inside surfaces of the side walls below the slot base, and the slot base. The top and side walls may also include a plurality of stabilizing recesses and stabilizing notches. The corners are also equipped with stabilizing recesses.