Lightweight Lycra XCEL Mens Short Sleeve Rash Vest for total sun protection or added warmth under a wetsuit. Xcel designed product from the original yarn through to the final design in 8 ounce spandex. Delivers SPF 50+ sun protection, added warmth under a wetsuit & protection from wax rash & wetsuit rash. Features a waist elastic which can hitch at the front to your boardies to keep it tight. Sizing Your rash vest needs to be a tight initial fit to be most effective. It will loosen as time goes by so a good fit is important. Small: 37 Chest Medium: 39" Chest Large: 41" Chest Xtra Large: 43" Chest "