Rubber sole The wider collar opening has been specially developed for female ankles. It is lined for a soft, comfortable feel. Nike React technology provides a responsive running feeling with light, durable foam. The higher foam gives you a soft wearing feeling with every step The rubber outsole has a traction specifically designed for runners in the city. The continuous mesh upper material improves air circulation. The tab on the tongue makes it easy to put on and take off. A midfoot strap ensures a secure fit.