A water bladder is a flexible container designed to hold liquids, primarily water. It is often made from materials like plastic or rubber and can be used for various purposes, including hydration during outdoor activities, camping, or emergency situations. Water bladders typically come with a tube for easy drinking, making them convenient for users on the go. These bladders are commonly found in hydration packs, which are popular among hikers and cyclists. They can also be used in military settings, where soldiers need to carry water efficiently. Overall, water bladders provide a practical solution for staying hydrated in various environments.