Sweet potato vermicelli is similar in texture to bean thread vermicelli, and turn transparent or glass-like when cooked - hence the name glass noodles or cellopane noodles. They are most widely used in Korean cuisine- where they're known as dang myun - to make japchae. 
 
To cook, soak in boiling water for 12-15 minutes. The sweet potato vermicelli noodles are packed in 4 x 100g nests. The noodles are an excellent gluten free alternative to wheat noodles.