Fresh Flat Rice Noodles
sen yai กํวยเตี๋ยวเส้นใหญ่
I remember seeing a fresh rice noodle machine once when I was a kid. It reminded me of a printing press, where the paper or noodles move from one spot to another and finally pile up in a receiving tray.
The noodles are made by steaming rice flour mixture on a flat surface. The noodles are soft and sticky. These are available in sheets or cut, about 3/4 of an inch wide. They are made fresh locally and don't keep very long, 3-4 days maximum, in the refrigerator. However, you can freeze the whole tray and thaw the noodles in the microwave. At my local Asian markets, the noodles come in white foam tray with plastic wrap. They are on shelves, not in the refrigerator. The noodles get hard when they are cooled in the refrigerator. If you are planning on stir frying them, heat them up in microwave for a few minutes and pull apart the strands. Otherwise, they will clump together, more difficult to season.
When ordering noodles in Thailand you will be asked what kind you want - this one is called "sen yai".