With Its Upgraded Leak-Proof Design And 2L/3L Tpu Water Bladder, The Zacro 2L TPU Leak-proof Hydration Bladder: Hydropack includes a 2L water pouch made of food-grade TPU material, ensuring it's 100% BPA-free and a switch valve and cover cap make it double leak-proof. With a 3.5-inch large opening, making it easy to add ice and clean. Ergonomic customized Design: The padded shoulder straps and mesh back pad are highly ventilated and breathable. Its low-profile athletic cut with full adjustment fits all body types comfortably. Also, the adjustable waist strap secures the pack snugly in place, provide you to customize the fit for maximum comfort. High-quality Material: Crafted from high-density nylon material and robust SBS zippers, Zacro hydration pack excels in outdoor durability. It is not only scratch-resistant, but also effectively repels rain. Additionally, the backpack features reflective strips to enhance safety during night travel. Well Organized Space: Water backpack bag for hiking boasts a generous 12.5L capacity, providing ample room for all your essentials. It features multiple compartments to keep your belongings organized and secure, with functional and separate pockets ensuring everything stays in place. Compact Ultra-lightweight: Runner backpack is tailored for cycling,running, hiking, trail, camping and even music festivals. Weighing only 8.5oz, it's compact and lightweight, ensuring comfortable wear throughout entire trek,also a practical gift idea for men and women.