nylon Imported Hydration Bladder Included: Comes with a 2 L BPA-free TPU hydration bladder; leak-proof and pressure-resistant for convenient hydration without stopping or removing your running vest Breathable and Adjustable Fit: Lightweight water vest with soft, moisture-wicking mesh padding; adjustable chest and waist straps ensure a snug, bounce-free fit for comfortable long-distance or trail running Ultra-Lightweight Running Vest: Weighs just 8.8 oz; wide, breathable shoulder straps distribute weight evenly to reduce fatigue and improve performance in marathons, cycling, or hiking Multiple Storage Compartments: Features six pockets for storing water bottles, phone (up to 6.1 inches), keys, gels, and cash; large rear pocket holds a 2 L bladder or a lightweight jacket, perfect for running vest man and hiking vest women Versatile Hydration Backpack: Durable and water-resistant hydration pack backpack suitable for marathon, hiking, cycling, jogging, and backpacking; available in multiple variations to meet different hydration needs Stay hydrated and focused with this ultra-lightweight hydration running vest, designed for runners, hikers, and outdoor athletes. Whether you're training for a marathon, trail running, or cycling, this vest offers hands-free hydration and smart storage without adding bulk. The breathable mesh back and wide shoulder straps keep you cool and comfortable, while the adjustable chest and waist straps ensure a bounce-free fit. Sized for versatility, the vest is easy to adjust and fits a wide range of body types—great for both standard and plus-size users. With multiple front and rear pockets, you can easily store soft flasks, keys, phone, snacks, and a hydration bladder or jacket. Available in different configurations to meet your needs—choose from models with soft flasks, hydration bladder, or vest only.