Nike Calm Mules. Enjoy a calm, comfortable experience—no matter where your day off takes you. Made with soft yet supportive foam, the minimal design makes these mules easy to style with or without socks. And the heel strap is both adjustable and removable to give you a personalized fit. Contoured design is made from a single piece of foam for a smooth, seamless feel. Subtle texture pattern on the footbed adds grip even when wet. Side cutout adds just the right amount of breathability. Outer shell is made from water-friendly foam that is easy to clean. Rubber outsole gives you excellent traction even on slippery surfaces. Removable heel strap. Imported.