Unbeaded Channels With Steel Core have a rubber covering, where used, gives long-life protection against corrosion, noise and rattles.  Inside lining, whether wool or polypropylene pile, felt or special fabrics, is tightly woven for maximum glass cushion.  Colors won’t fade.  Flexible steel core, whether perforated or corrugated, forms easily and quickly for a perfect fit to any contour without pulling or stretching.