100% polyester; anti-microbial, anti-static, anti-odor and UPF 50 protection; sideseamed; double-needle topstitch on bottom hem and side vents; clean-finished inside neck with self-fabric neck tape; proven to absorb, wick and evaporate more moisture than cotton; quick drying and breathable; set-in sleeves with open hem; three-button placket with flat-knit collar. Tone on Tone embroidery - to match shirt unless traditional red/white logo requested.