100% PolyesterDri-FIT mesh fabric wicks away sweat to help keep you dry and comfortableReflective loop at upper back to keep media-player cords out of the wayErgonomic seams are rolled forward for comfort and the body-mapped design enhances your natural range of motionDri-FIT mesh panel in the middle back is knit from loose to tight with three different textures for varying degrees of coolingReflective details for enhanced visibility in low light conditions <br /> <ul> <li>Dri-FIT mesh fabric is knit from loose to tight for zoned breathability.</li> <li>Mesh opens up down the middle back for optimal breathability.</li> <li>Scoop-neck design provides a flattering, nonrestrictive fit.</li> <li>Body: Dri-FIT 135g. 100% polyester circular knit jacquard. Mesh: Dri-FIT 130g. 100% polyester circular knit jacquard.</li> </ul>