Nike Dri-FIT Challenger Big Kids' (Boys') Training Shorts. An essential for running laps, chasing down tennis balls, playing soccer or just good old-fashioned playing during recess, these cool, comfortable shorts help you do it all and have fun, no sweat. What makes these extra special? You can keep your phone or media player in the back pocket! Now you're ready to rock. Nike Dri-FIT technology moves sweat away from your skin for quicker evaporation, helping you stay dry and comfortable. Stash your snacks in the mesh side pockets. Tighten up the waist on the go with the quick-tie drawcord. Mesh side panel and hem slit help you stay cool and carefree. 100% Polyester.