Specific commercial products of ionomer resins include Himilan (Dupont-Mitsui Polychemicals Co., Ltd.), Surlyn (E.I. Dupont de Nemours and Company), Iotek (Exxon Chemical Company) and T-819 (Dainippon Ink & Chemicals, Inc.). [0112] It is noted that inorganic fillers and other additives may be blended in the cover-forming resinous material, as illustrated above in conjunction with the surrounding l