The Arc'teryx Taema Crew Neck Long Sleeve Shirt - Women's is a synthetic base layer for moving fast in cool conditions. Hiking, trail running, getting to the top of the mountain, whatever your activity entails, the Phasic engineered polyester fabric is here to help. It wicks moisture, dries quickly, and leaves you feeling totally comfy every step of the adventure. The fabric stretches for unrestricted movement and the UPF 40 sun protection keeps harmful rays of sun off the skin.