Pertexâ Eco Microlight is made from TEIJIN Fibres Limited's ECO CIRCLEÔ recycled polyester yarns. The fabric is densely woven, and because of this it is not only windproof, but also prevents convective heat loss through the fabric (when used in insulated apparel). Eco Microlight has a soft handle, which allows the insulation to have more loft, it also packs small and has a very high level of water repellence.