Lightweight performance tee with Solar-Factor UPF 40+ UV Protection and Moisture Wicking Technology. Solar-Factor UPF 40+ UV Protection Moisture Wicking Technology Performance Stretch Lightweight Polyester/Spandex Soft Seaming for Added Comfort Specs Body: 95% Polyester, 5% Spandex Machine wash cold with like colors, only non-chlorine bleach when needed, tumble dry low, remove promptly, cool iron if needed Sizing and Fit Model is 6'1" and 215lbs. He is wearing size Large. Relaxed fit for extra comfort and mobility, if you think you are between sizes best to buy the smaller size.