Features of the Smartwool Women's Merino Sport 150 Short Sleeve Top Moisture management, temperature regulation, and odor resistance of merino with the durability and quick dry time of polyester Flatlock seam construction designed to minimize chafing Mesh in key Areas designed to increase breathability and comfort during strenuous activities Knotted twist detail with keyhole opening at back Fabric Details 54% Merino Wool, 46% Polyester