The neck and the shoulders are the parts where the body loses most of the body temperature. It explains the habit (and desire) of many people to wear a scarf in winter.
This ‘hot drop’ filled with cherry-stones can be heated up by putting it on top of the heater, in the oven or microwave. You can wear it underneath your cloths and it will give you warmth for 45 minutes. The front can be worn as a accessory, like a piece of jewellery for example, because it is not necessary to hide all that you wear.