Sanctuary from sun and chill alike: This hardworking top is made of a stretchy blend of quick-drying, 5.8-oz 84% polyester (100% recycled)/16% spandex with built-in 30-UPF sun protection. Its seamless underarm gussets let kids move naturally during swimming, boarding or castle-building. A low-profile mock turtleneck design provides neck coverage; flat-seam construction throughout keeps the action friction-free.