Who does not know this from the past? If you had a stomach ache, you always had a heat pad from the oven. Unlike hot water bottles, heat pads store heat really well and release it in a targeted manner.
By the way, they are also highly recommended for back or abdominal pain.
This one comes from the traditional Swiss company Albis and is filled with cherry stones. If you want, you can get a refill bag with the pillow. Herewith you can refill more cherry stones at any time. The practical zipper makes it possible.