Smart, simple accessory attaches a 500ml flask to your pack’s shoulder strap. Keep hydration right at hand. With a universal attachment that works with all of our trail, climbing, and backcountry ski packs, the Della puts the included 500ml flask right on your shoulder strap. Made from PowerMesh, and designed for easy use on the move, the holder wraps the flask for a snug, secure hold with minimal bounce. Full Product Features Pack Design & Construction - PowerNet stretch nylon fabric is light, durable, and stretches for a secure carry Pack Hydration - Arc'teryx 500ml flask included Materials - Powernet Stretch Mesh—83% nylon, 17% spandex. Stretchy, resilient mesh fabric. - 100% Polyester