Under Armour T-Shirt Youth Boy Size 6 orange. The Under Armour T-Shirt for youth boys in size 6 is a stylish and comfortable option for young boys. Made from a blend of 50% polyester and 50% cotton, this short sleeve shirt in orange color is perfect for active kids. With the reputable Under Armour brand, you can trust in the quality and durability of this t-shirt for your little one.