READY TO TRANSFORM. Go from fanny pack to vest and back again with 1 versatile design: the Nike Transform Vest. Lightweight fabric designed for maximum breathability folds into a zip pocket on the integrated fanny pack when your needs are minimal. You can find a custom, stable, comfortable fit with the adjustable chest and side straps and multiple stretchy mesh pockets give you plenty of room to store essentials and easy access on the go. [] Product Details:Whistle on the front. Body:94% polyester/6% spandex. Lining:82% polyester/13% nylon/5% spandex. Imported. Style: N1002042; Color: Black/Black; Size: S/M; Gender: Unisex; Age Group: Adult | Nike Transform Packable Running Vest in Black, Size: S/M | N1002042-013