Abstract: An elastomeric seal having substantially hollow body having a polygonal cross section formed by a bottom wall, a pair of opposed spaced side walls, a top wall and a plurality of internal supporting struts symmetrically arranged about the center of the polygonal cross section. The top wall is formed of a pair of arms extending in a V to each other, the apex of which lies along the center line between the side walls. The side walls are themselves bent inwardly intermediate their ends to extend perpendicular to the respective arms of the top walls. Compression of the parallel side walls, toward each other, causes the inwardly bent portions of the side walls to rotate outwardly resulting in a raising of the apex of the top wall so that the top wall assumes a flat configuration.