This The P.I. Performance Polo Shirt by Chubbies features moisture-wicking, anti-bacterial, anti-static, UPF 50 , and unparalleled breathability. Tailored Fit: Recommend Sizing Up for a More Relaxed Look. This Chubbies The P.I. Performance Polo Shirt is made of 90% Polyester, 10% Spandex.