Breathable, ultra-light, and waterproof, this running vest is made from durable, waterproof nylon fabric to keep you dry and cool. The breathable mesh back effectively wicks away sweat and dissipates heat. Weighing only about 160 grams (approximately 14 x 7 inches), this ultra-light vest is perfect for long-distance running or hiking. Practical pockets and a smart layout: This running vest features five external pockets, including a zippered cell phone compartment. The main back compartment holds a 1.5-liter hydration bladder and has a buckle to secure your belongings. Other pockets neatly organize and are easily accessible for items like energy gels, snacks, keys, cash, and other essentials. Emergency whistle: The built-in survival whistle provides extra safety during outdoor activities, especially suitable for safety-critical situations such as hiking, trail running, or long-distance running. Adjustable and secure fit: Two adjustable chest straps effectively reduce movement and friction during running and exercise. This vest conforms to your body for a stable and comfortable fit. Reflective details enhance visibility at night, making you safer when running at night or early in the morning. Package includes: 1 running vest (Note: Hydration bladder not included. The vest can accommodate a hydration bladder with a capacity of no more than 1.5 liters.)