World Centric, compostable flat, clear lids for 20-48 oz fiber boxes are made from PLA, (polymer made from plants). They are suitable for cold liquids, and freezer safe. Not microwavable. This lid has a flat surface with our embossed logo at the bottom to provide a place for a business to customize with a label. PLA products should be stored in a cool place below 110F and out of direct sunlight. These are certified compostable in a commercial facility, which may not exist in your area.