Safe & Easy to Use: The wide mouth design prevents you from getting burned when filling water, and it is easy to quickly and safely pour water into the hot bottle water bag without overflowing. Note: Please fill in two-thirds of hot or cold water. Cold & Hot Compress: Compared with traditional rubber hot water bottles, recyclable thermoplastic materials, advanced thermoplastics hold the heat for up to 8 hours, also work as an ice pack or water heating bag. But please be noted that this warm water bottle is not suitable for microwave use. Non-toxic, Odorless & Harmless: Hot water bottle for cramps does not contain BPA, phthalates, and other harmful ingredients. The non-charged hot water bottle is easier to carry. You can use them anywhere with confidence. It is also a good choice for holiday gifts! Good assistant: Using the hot water bottle with soft cover can relieve menstrual cramps, muscle aches, and pain in various parts of the body. Drive out the cold in winter to keep warm, and cool down in summer with cold compresses.