The Smartwool NTS Midweight 250 Women's Half-Zip Running Top is comprised of a 100% Merino Wool construction which offers you supreme quality, warmth and comfort for enhanced performance. The form fitting fabric offers the runner superb benefits over traditional synthetic materials, with excellent breathability properties, durability and odor control, as well as improved dirt and water resistance. Seamed panels also contour to your shape for a body enhancing fit whilst shoulder panels eliminate top shoulder seams which can cause irritation. The half zip design is also ideal for secure fitting, quick venting and easy on and off of the garment, great for use as part of a layering system or to wear on its own.