100% polyester; 40 UPF on White; 30 UPF on other colors; Wicks moisture and keeps the body dry; Anti-microbial treatment prevents odors from perspiration; Double-needle stitching on sleeve and bottom hem for strength; Comfortable fit; Sideseamed; Set-in sleeves; Self-fabric collar and tagless neck labeling; Neck seam has double-needle front stitch & overlocking back stitch for strength