The Mens Long Sleeve Rash Vest can be worn for swimming, under a wetsuit or when you spend time in the sun: It's made of soft, stretchy fabric with UPF 50+ treatment and flat seams: a lightweight sun protection top: Fabric composition: Made of 82% nylon and 18% elastane UPF 50+: the fabric has a sun protection treatment of 50+ Quick drying: Suitable to wear in and out of the water. Flat seams. Combined with a close fit to prevent chafing, perfect to wear under a wetsuit or as part of a swimming costume Comfort. soft, stretchy fabric feels comfortable on the skin.