Nike site: Soft fabric is designed for breathability on the front and back in case you work up a sweat. With easily removable pads and bonded flat seams, it's effortlessly comfortable. This product is made with at least 50% recycled polyester fibers. Easy Adjustment Mini Nike logos on the front of the straps let you make quick adjustments without having to bend over backwards to get the right fit. Breathable Design Mesh side panels shaped like Swoosh designs take breathable style to the next level. The V-neck and mesh at the center front also help keep the air flowing. Sweat Wicking Nike Dri-FIT technology moves sweat away from your skin for quicker evaporation, helping you stay dry and comfortable.