pork neck bones
Meaty vertebrae from the pork neck that give a rich, slightly gelatinous broth when simmered for a long time.
Pork neck bones are common in many North American supermarkets but rarely on display in German-speaking countries, where a butcher will usually set them aside if you order ahead, and Asian grocers with a meat counter often stock them frozen. Ask for pieces with plenty of meat left between the vertebrae.
Substitute:
Pork back bones work just as well, and spare ribs will do, though they give a somewhat less rich broth and less tender meat to pick off the bone.