Features of Smartwool Men's Merino Sport 150 Overland Trek SS Graphic Tee Fabric combines the moisture management, temperature regulation, and odour resistance of Merino with the durability and quick dry time of recycled polyester Flatlock seam construction designed to minimize chafing Offset shoulder seams designed to increase comfort UPF 20+ Fabric Details 56% Merino Wool, 44% Polyester. Exclusive Of Decoration. 56% Merino Wool, 44% Polyester. Exclusive Of Decoration.