Under Armour Boys HeatGear Armour Short Sleeve Fitted Shirt 90% Polyester, 10% Elastane Imported HeatGear fabric is ultra-soft & smooth for extreme comfort with very little weight UPF 30+ protects your skin from the sun's harmful rays 4-way stretch construction moves better in every direction Material wicks sweat & dries really fast Anti-odor technology prevents the growth of odor-causing microbes