Under Armour Men's UA HeatGear Armour Printed Short Sleeve Compression Shirt Mesh: Polyester/Elastane HeatGear fabric, with all the benefits of UA Compression, comfortable enough to be worn all day Stretch-mesh underarm panels deliver strategic ventilation UPF 30+ protects your skin from the sun's harmful rays 4-way stretch fabrication allows greater mobility in any direction Moisture Transport System wicks sweat & dries fast