SWEAT-WICKING PERFORMANCE FOR THE PITCH. The Nike Dri-FIT Park 7 JBY Jersey features smooth, sweat-wicking fabric with mesh on the back to help keep you dry, so you can stay focused from the opening whistle to the 90th minute. This product is made with 100% recycled polyester fibers. Dri-FIT technology helps keep you dry and comfortable. Mesh on the back adds breathability.