Cellophane noodles, or fensi (), sometimes called glass noodles, are a type of transparent noodle made from starch (such as mung bean starch, potato starch, sweet potato starch, tapioca, or canna starch) and water. A stabilizer such as chitosan (or alum, illegal in some jurisdictions) may also be used. They are generally sold in dried form, soaked to reconstitute, then used in soups, stir-fried dishes, or spring rolls. They are called "cellophane noodles" or "glass noodles" because of their cellophane- or glass-like transparency when cooked. Cellophane noodles should not be confused with rice vermicelli, which are made from rice and are white in color rather than clear (after cooking in water). Varieties Cellophane noodles are made from a variety of starches. In China, cellophane noodles are usually made of mung bean starch or sweet potato starch. Chinese varieties made from mung bean starch are called Chinese vermicelli, bean threads, or bean thread noodles. Chinese varieties made from sweet potato starch are called Fentiao or Hongshufen. Thicker Korean varieties made with sweet potato starch are called sweet potato noodles or dangmyeon. Cellophane noodles are available in various thicknesses. Wide, flat cellophane noodle sheets called mung bean sheets are also produced in China. In Korea, napjak-dangmyeon (literally "flat dangmyeon") refers to flat sweet potato noodles. Production In China, the primary site of production of cellophane noodles is the town of Zhangxing, in Zhaoyuan, Shandong province. However, historically the noodles were shipped through the port of Longkou, and thus the noodles are known and marketed as Longkou fensi (). Use East Asia China In Chinese, the most commonly used names are fěnsī (, literally "noodle thread") and fěntiáo or hóngshǔfěn ( or , literally "noodle strip" or "sweet potato noodles"). They are also marketed under the name saifun, the Cantonese pronunciation of the Mandarin xìfěn (; literally "slender noodle"), though the name fánsī (粉絲) is the term most often used in Cantonese. In China, cellophane noodles are a popular ingredient used in stir fries, soups, and particularly hot pots. They can also be used as an ingredient in fillings for a variety of Chinese jiaozi (dumplings) and bing (flatbreads), especially in vegetarian versions of these dishes. Thicker cellophane noodles are also commonly used to imitate the appearance and texture of shark's fin in vegetarian soups. Thicker varieties, most popular in China's northeast, are used in stir fries as well as cold salad-like dishes.