ADJUSTABLE stretchy belt fits securely and comfortably as you run. EXPANDABLE pocket holds your small essentials. CONTOURED, lightweight design for comfort and less bouncing. EASY single-button closure on belt. Made with 38% NEOPRENE, 25% POLYESTER, 13% NYLON, 13% ALUMINUM ALLOY, 11% THERMOPLASTIC POLYURETHANE. Small but mighty, this running belt from Nike is made from stretchy material and adapts to your needs. Depending on your requirements, the pocket expands to easily accommodate bars, handkerchiefs, and keys. The large reflective area around the zipper also lets you glow in the dark, ensuring your safety. The Slim Waistpack 3.0 can be worn over the shoulder or as a waist belt, features a zippered pocket, a conspicuous reflector on the front, and a click fastener.