1. Large opening facilitates cleaning and filling: Large opening facilitates pouring water. It is also quite wide, making it easy for hand brushes or bottle brushes to enter the internal hydration bladder. The nut that is screwed on is easy to screw on and off. For cold water, simply add ice cubes directly from the spoon or ice dispenser in the refrigerator. The interior of the reservoir is smooth, promoting health and easy to clean.2. High quality: The entire hydration tank is made of high-quality EVA material. The water bag is odorless, and this test meets international safety standards. It won't leave a bad taste in your drink. The water bag has passed the air pressure test and has pressure resistance. Double sided sealing technology greatly improves durability.3. Maintain sufficient hydration. The water temperature in this 2L reservoir should not exceed 60 degrees Celsius, otherwise the bag may be burned and drinking beverages or dairy products is prohibited.