When your performance actually matters, ditch the cotton tee and upgrade to the Arc'teryx Women's Senna Tank Top. Your torso deserves better than moisture retaining cotton. This strappy tank offers an outer later composed of the awesome Haven material, a single knit polyester jersey fabric with spandex for supreme mobility on that precarious rock face or nigh vertical trail. Inside, the Senna includes a convenient built in shelf bra with insert pockets for adjustable support and comfort. Composing the shelf bra is Aerial polyester, a lightweight mesh lining with moisture wicking superpowers. Arc'teryx has treated the Aerial mesh with a Polygiene finish to battle the forces of odor with miniature viking warriors. The Senna sports a full coverage length to take advantage of its UPF 50 rating, high quality sun protection.