NEXT-LEVEL SUPPORT AND FLEX. The Nike Pro Flex Shorts pair built-in shorts with a stretchy outer layer to keep you feeling supported and moving naturally. Mesh panels help you stay cool when your workout heats up. Made to move: Nike Flex fabric stretches with your body, helping you get the most out of your performance – without getting in your way. Supportive coverage: built-in shorts have a tight fit to help you feel supported through your routine. Secure comfort: an exposed elastic waistband provides a stay-put fit and a smooth feel. Mesh on the sides lets air flow to help keep you cool.