This sleeveless shirt is made of 1.5 mm breathable Airprene material that allows your skin to breath and prevents the feeling of overheating. The big openings for your arms allow a free movement in the shoulder area. It keeps the upper body and chest warm when the weather gets too cold for an UV shirt. It is designed with a practical pocket on the back to put in any accessories you may need. Combine our AIR SLEEVELESS with our AIR SHORTS or AIR LONG PANTS for maximum warmth.