SPEEDO Men's Fitness Rashguard Snug fitting for a looser fit, size up. UV Block the Burn? protective fabric features: More body coverage for greater sun protection. Tighter knit fabric for higher level of protection from the sun's harmful rays. Improved fit so over-stretched product does not decrease the UPF rating. Short sleeves with contrast accent splicing. Lightweight and quick drying. Fabric: 80% Nylon/20% Xtra Life LYCRA? fiber.