Arc'teryx Rho AR Zip Neck Women's Polartec Power Stretch - 90% Polyester, 10% Elastane Imported RHO AR ZIP NECK - Excellent thermal mid-layer for aerobic activities or expedition weight insulation for cold winter sports. Form fitting versions feature Polartec Power Stretch, which wicks moisture and prevents constriction. ALL ROUND - High performance weather protection and materials, emphasizing versatility for multiple activities. ARC'TERYX ESSENTIALS - Versatile high performance designs for diverse activities and conditions. POLARTEC - Synthetic fleece textiles with stretch, warmth and air permeable properties. Offers durability. RHO - Thermally efficient base layer with excellent moisture management properties. Has stretch comfort.