This high-performance technical shirt is great as your only layer in warm weather and as an under layer in cooler conditions. Double Circular Knit polyester is lightweight, breathable, dries quickly and has a wicking finish to move moisture away from your body. While still offering maximum UV protection. Sizes: Chest Size Small: 42 inches Medium: 44 inches Large: 46 inches X Large: 48 inches XX Large: 50 inches