【Ergonomic Design】The Ryaco hiking backpack's hydration vest conforms to the curves of your back, with breathable mesh fabric keeping your back cool and promoting airflow, effectively reducing heat and sweat during exercise and providing excellent breathability. 【Ultra-Lightweight and Convenient】Made with high-quality waterproof, scratch-resistant, and tear-resistant nylon fabric, the ultra-lightweight design makes it more comfortable to use and exercise. Weighing only 300 grams, the main compartment has a capacity of up to 2L. The hydration bladder is BPA-free and leak-proof. 【Perfect Combination】This lightweight cycling backpack features adjustable waist and shoulder straps to fit your body shape, with a perfect size for most people, both men and women. 【Safe and Reliable】Reflective trim enhances safety during nighttime activities. Numerous pockets and zippered pockets of various sizes are located on the front and back of the backpack, making it convenient to store energy foods, tissues, towels, mobile phones, keys, and other items for quick and easy access during exercise. 【Versatile Use】This hydration pack is designed for a variety of occasions including road cycling, running, hiking, mountain biking, cycling, rock climbing, and music festivals. It features a compact structure, small size, lightweight stability, and low wind resistance. Ideal for both men and women, it's suitable for various sports such as cycling, hiking, running, skiing, mountaineering, hunting, competition, and training. A wonderful gift for friends and family who enjoy outdoor activities.