Gore Bike Wear Men's Base Layer Windstopper Thermo Long Shirt 100% Polyester Imported Flat-lock seams Windproof long sleeve shirt for windy and cold days. Helps keep you warm and provides quick moisture management. Protects from cooling in breast, shoulder and kidney area. Tight fit Elastic WINDSTOPPER insert on front, at sleeves, over shoulders and on kidney area Thermo-stretch functional fabric Minimized seams for less chafing Flat-lock seams