BRIEF DESCRIPTION OF THE DRAWING [0015] To facilitate the understanding of the foregoing ideas, there is described hereinafter one embodiment of the invention, with reference to the accompanying drawings, in which: [0016]FIG. 1 is a perspective view of an open narrow annular member forming the retainer device of the invention. [0017]FIG. 2 is a front elevation view of the retainer device of FIG. 1