Are you talking about the kind with an air outlet on top and a handle next to it? It is made of pp material and can be used in a microwave oven and can be used to make noodles.

You can look at the bottom of the box. There is a triangle with numbers (1-7, plastic grade) inside. Only 5 and 7 can go into the microwave. For instant noodles, 5 and 7 can be used. 6 is also food grade, but It’s best not to use it for instant noodles. It can be used to store cooked food at room temperature.

The other grades 2 and 3 are industrial materials, 1 is bottled water, and 4 is generally used as plastic wrap.