The lids have enough elastic allowing you to have a secure cover for a variety of different containers. 6 sizes for you to choose, different size fits your different needs. Made of non-toxic and environmental silicone material, practical and durable to use, easy to clean. The silicone lids made of 100% food-grade silicone approved dishwasher and freezer safe and Microwave-safe & heat-resistant to 450 F come out the same as you first saw it.