Splash around in the Nike Boys' Just Do It Long Sleeve Hydroguard Swim Shirt. It is made of 100% polyester. The Dri-FIT technology keeps you dry, and its UPF 40 UV protection helps you stay protected from the sun. The "Just Do It" across the chest finishes off the design. Nike Boys' Just Do It Long Sleeve Hydroguard Swim Shirt Black, Large - Boy's Swim at Academy Sports