Happy Heat Bottle Collection is the next generation of heat therapy. Perfect to provide soothing relief from workouts, menstrual cramps or general pain. The water is permanently pre-sealed, so there is no need to refill and /or to empty the water after each usage. A 100% natural heat treatment with no chemicals. Easy to use: plug the cord for 15 minutes, unplug it and the unit stays warm up to 5 hours (longer than any ordinary hot water bottle).