Use one time, Comes with the 2L water bag big can be replaced. Hiking Optimized Design: This hiking hydration backpack with bladder is purpose built for hiking outdoor adventures, featuring a dedicated compartment to securely hold the included 2L water bladder. The leak-proof and taste-free water bladder ensures a clean and pure drinking experience, while keeping your gear dry and protected. Lightweight Performance: Designed with lightweight and waterproof Nylon materials, this lightweight insulated hydration backpack minimizes the weight burden on your shoulders, allowing for comfortable and unhindered hiking and running. You can move freely and effortlessly, focusing on the beauty of the trail without feeling weighed down by a heavy pack. Advanced Insulated Hydration Backpack: Miracol specialized insulated hydration pack equipped with cutting-edge insulation technology that preserves the coolness of your water for 4 hours, regardless of external temperatures, this ensures that you can stay hydrated and refreshed throughout your hike, even in hot weather conditions. Adjustable Straps for Custom Fit: This hydration backpack with a bladder comes with a sternum strap and waist belt that can be easily adjusted to fit your body type. These customized straps ensure maximum comfort and stability on your hike without discomfort or slippage, so you can keep pace and enjoy the ride.