I bought these to get rid of all my plastic storage bowls. I wanted to switch from the opaque/softer plastic storage containers to glass containers, mostly because I can't stand how easily the opaque ones stain and melt. These glass containers have no chance of that, and the lids sit on top of the container and aren't going to come in contact with the food. The glass portion is oven, microwave and dishwasher safe. Because they are made of thick glass, they are perfect for leftovers that you want to reheat later in the oven. The set has 3 different sizes making this set perfect for any of your storage needs. They are the perfect addition for my kitchen needs. I love how they can go from the freezer to the oven, refrigerator to the microwave, they have a perfect air tight seal that means no more freezer burnt food. You can now feel confident that you are storing your leftovers properly.