OccuNomix Super Heavyweight Fleece Liner For soft comfort and excellent warming, this charcoal gray, single layer liner is made of 100% super heavyweight polyester fleece with a long neck design. Liner features warming pack pockets lined with DuPont Thermotex microporous material, elastic gap eliminators, and a reflective strip on the back. Fleece and fasteners are flame resistant, binding is flame retardant until washed.