1.BPA FREE MATERIALS Made of food grade materials, it is odorless, nontoxic, BPA and FDA approved, does not produce unpleasant odors and keeps your drinking water clean. 2.Large opening: 8 cm, the nut opens easily. The large opening design makes it easy to fill/refill water and ice. The large opening design fits the whole hand into the hydration bladder, which is easy to clean, you can clean the hydration bladder with your hands or a brush without missing the corners, making your hydration bladder very clean. 3.Leakproof design: with a soft silicone valve, you can achieve a large flow of water with just one bite. The mouthpiece can be closed by pressing and opened by pulling. The sturdy cap prevents dust from sticking to the mouthpiece. The hydration bladder tube is very easy to insert and remove. When you remove it, the automatic shutoff valve prevents water leakage. 4.READY FOR THE ADVENTURE With a capacity of 2 liters, this hydration bladder can be used to keep you hydrated during outdoor sports, and measures 36 x 17 cm, which fits most hiking bags and hydration packs. It can withstand temperatures from 20 degrees Celsius to 50 degrees Celsius and has excellent effects in both hot and cold weather.