The comfiest tee to pair with a running vest. Whether you're running in the mountains or on your local trails, the Cirriform Tee's seamless shoulder area is optimized to be worn comfortably under a hydration vest. Mesh body mapping at the body's highest sweat area and quick-wicking fabric provides all day breathability and comfort. Features Body mapped mesh at the back for increased breathability in the body's highest sweat areas Soft, quick-wicking fabric at the front Seamless shoulder design for maximum comfort and compatibility with running vests and packs Materials Primary Fabric: 87% polyester 13% spandex Secondary Fabric: 6% polyester 83% cationic 11% spandex Specs Center Back Length: 27.5" / 69.85 cm Sleeve Length: 17.75" / 45.08 cm Weight: 4.69 oz / 133.0 g | Ultimate Direction Men's Cirriform T-Shirt in Onyx Size Small