Skins Men's A400 Long Sleeve Top Nylon 76% / Spandex 24% Imported 76% Nylon, 24% Spandex More oxygen to your muscles. World's first Dynamic Gradient Compression delivers more oxygen-filled blood to active muscles, increasing endurance, power, and efficiency. Built for motion: Hem gripper around the waist, stretch airflow mesh under the arms, and taped and bonded sleeves ensure maximum comfort and support in any activity. Cold machine wash, gentle cycle, with like colors. Do not bleach, iron, or tumble dry.