This hot water bottle is made of ecofriendly PVC and is designed to provide relief from neck and shoulder pain. It can also be used for menstrual cramps, hand and foot warming, and as a hot compress. The bottle is approximately 24.5 x 16.5cm in size. To use, test with cold water, then add hot water to 2/3 of the product capacity, exhaust the air, install the cover, and check for water leaks.