Big Kids' (Boys') Training Top Get ready to kick it into high gear in the Nike Dri-FIT Miler Top. Breathable fabric and Dri-FIT technology help keep you cool and dry when you're playing hard. This product is made with at least 50% recycled polyester fibers. Dri-FIT technology helps you stay dry and comfortable. Breathable fabric helps you stay cool. 100% Polyester.