Sold with the bristles singed off and the fat scraped away. Long boiling makes it soft and chewy and draws out its collagen, which sets into a jelly eaten cold and melts into the soup inside soup dumplings.
Two main uses: cuisine (猪皮冻 "pork-skin aspic," 炸猪皮 "crispy pork rinds" - popular in Northern Chinese and Cantonese cooking) and material (cheap leather for shoes/bags, considered lower-grade than 牛皮 cowhide).