In my opinion, these storage containers are the best! I don't like to store food in plastic, so I was looking for something in glass, but with a lid that was secure and tight - OXO is perfect. The lids fit super tight, with snap down lids on four sides, keeping the food secure. This particular set is clear, allowing you to see the contents, and the four bowls are stackable, and can nest inside each other to take up less storage space. I have used the bowls in the microwave, oven, and refrigerator, but have not used in the freezer - they are advertised as being freezer-safe as well. I love this brand, and this set comes with four conveniently sized bowls ranging from one to seven cups. Highly recommended.