Naigu's family of internal medicine is very strict in the selection and control of materials. For example, pure gold clavicle chains matched with various kinds of jewelry are divided into 10K (labeled as 9K in China), 14K and 18K, among which the gold content is different and the hardness is slightly different, and 10K has the highest hardness, so it can create more exquisite shapes and designs. It is more expensive, extracted for a long time, and does not contain allergic metal substances, so there will be no allergies unless someone is allergic to pure gold or jewelry.