Long Sleeve Zip Mock Neck features our patented IceFil technology fabric. It works by converting sweat to refrigerant; cooling your skin 3 to 5 degrees, allowing you to be cool, comfortable and dry on the hottest humid days. This garment also has built-in UPF 50 sun protection, moisture-wicking, and anti-microbial properties. This style has a mesh underarm pa92% Nylon, 8% Polyurethane.