A 1960s mini dress and medical packaging were the inspiration when it came to redesigning Nike's original PreCool Vest. First introduced in Athens, Nike wanted to make it lighter, more flexible, better fitting and refillable a tall order for a piece of equipment athletes have been praising since Athens. The vest is designed to cool the body's core temperature. Since 25% of our body's total energy goes into moving muscle and 75% into regulating heat, reducing an athlete's core temperature before the marathon or a field hockey match means more energy for the competition itself. Indeed, with core cooling, athletes can often last 21% longer. Given Beijing's hot and humid conditions, the PreCool Vest is a key piece of equipment that can help provide the advantage an athlete needs.