Chinese antique copper handwarmer

Below is a memento from a trip to China circa 1979. It is a small  handwarmer that might have been filled with coal for warmth. While an artifact of Chinese culture it is very much a memento to me.  I was in China and saw coal barges on the rivers and visited some homes that were heated by coal.  It was November. The hand warmer was bought by me from a government store. It celebrated the warmth of the hospitality provided to my travel group by our tour guides as the seasons turned cold in the northern cities.  I imagined the tiny bit of warmth from the hand warmer combined with a warm coat of cotton covered in silk keeping the original owner warm.  It was mailed to me suffering a bit of damage but I still treasure the memory of its purchase.