plastic.
Just saw them at costco, but its a kit and many sizes might be useless. Once you figure which sizes work best you will need more of them. I like the 2.x, 4.7, 7.3 cups.
Perhaps I wasnt clear on my comment about stacking. All the various sizes are the same basic size, just single or double wide and taller. Thats confusing but what it means is that two singles will have the same footprint as the double wide. The fooprints are compatible and the sizes vary vertically.
Just saw them at costco, but its a kit and many sizes might be useless. Once you figure which sizes work best you will need more of them. I like the 2.x, 4.7, 7.3 cups.
Perhaps I wasnt clear on my comment about stacking. All the various sizes are the same basic size, just single or double wide and taller. Thats confusing but what it means is that two singles will have the same footprint as the double wide. The fooprints are compatible and the sizes vary vertically.