Practical & Innovative Water Bladder: This hydration backpack has a large opening for effortless filling and cleaning. It features an automatic shut-on/off valve to avoid leakage, a 360° mouthpiece with a dust-proof cap to maintain hygiene, an ergonomic handle design for convenience and functionality. Experience a seamless and convenient drinking experience. 2L Practical Water Bladder: The hiking backpack with water bladder includes a food-grade TPU water bladder, ensuring a pleasant drinking experience. Its leak-proof automatic shut-on/off valve and sealed detection technology avoid leak risks, providing you with peace of mind. Durable & Waterproof Polyester: The running backpack is made from waterproof polyester material. It is tear-resistant and abrasion-resistant for various outdoor conditions. The brand zippers are tested 3000 times for long-lasting durability. Experience smooth and effortless use on adventures and long trips