Under Armour Kids - 4-Pack Core Cotton Boxer Set (Big Kids). Color Ultra Blue. Low Stock. On sale for $19.99. MSRP $22.00.. 4.4 out of 5 stars4 left in stock+2Brand NameUnder Armour KidsProduct Name4-Pack Core Cotton Boxer Set (Big Kids)ColorUltra BluePrice$19.99MSRP: $22.00Rating4Rated 4 stars out of 5(23)