Under Armour Kids - 4-Pack Core Cotton Boxer Set (Big Kids). Color Ultra Blue. On sale for $19.50. MSRP $22.00.. 4.5 out of 5 stars+2Brand NameUnder Armour KidsProduct Name4-Pack Core Cotton Boxer Set (Big Kids)ColorUltra BluePrice$19.50MSRP: $22.00Rating5Rated 5 stars out of 5(20)