High-Quality Materials The inner layer of this water bladder is made of PE material, and the outer layer is made of EVA material, which is wear-resistant and corrosion-resistant, BPA-free, odorless and non-toxic, and safe to drink.Leak-Proof Design: The water storage bag has passed the pneumatic pressure test and is completely pressure-tolerant. The double-sealed side technology greatly improves durability. It automatically closes when the tube is removed, and the included 2-liter water tank remains filled without leaking.Large Opening, Easy to Fill and Clean: The wide opening is enough for your hands to clean the water bladder, making it easy to add water and ice cubes. The large opening allows you to reach into the corners inside and thoroughly clean your water storage container.2L Large Capacity: This water bladder has a capacity of 2 liters. It is the best choice for outdoor use, enough for a day of hiking, cycling, mountaineering, running, or biking. The size is 34 x 17 cm, and the hose length is 100 cm, which is enough to drink directly from the backpack.Perfect for Hydration Packs: Compatible with most hydration packs, just fill it with fresh water and insert it into the backpack. To hydrate, gently bite the valve and sip like a straw. Perfect for various outdoor activities such as hiking, cycling, marathons, camping, climatology, running, skiing, jogging.