He'll show the ocean who's the toughest little guy in the sea. This fish-themed rashguard set offers UPF 50+ sun protection. The nylon/spandex rash guard offers UPF 50+ protection that stays strong for the life of the garment. The boys' swim trunks are made of quick-dry microfiber. They feature an interior mesh lining, cargo pocket and all-around elastic waistband for a perfect fit.