Callaway Mens Golf Performance Engineered Stripe Short Sleeve Polo Shirt 86% Polyester/14% Spandex Imported Opti-Dri: Transfers moisture away from the body to aid in evaporation Opti-Shield: create a layer of protection from the sun's harmful ways, UPF 50 Opti-Stretch: interwoven layers of spandex to ensure maximum range of motion so the garment moves with the golf swing