silicone can be used across a wide temperature range from -65 degrees F (-54 degrees C) to 450 degrees F (230 degrees C). REUSABLE AND SAFE Made of Food grade, BPA free, dishwasher safe silicone, these seals can be used over and over. One piece plastic or metal storage lids are super convenient when you are storing things in the fridge or pantry, but most of them are not air tight and leak proof. These seals will fix that. Practical performance: these airtight silicone gasket sealing rings are good replacements if your gaskets wear out, they can be applied for airtight sealing to keep your fruit, vegetables, jams, sauces preserved, it is effortless to wash and easy to assemble them Washable and reusable: these sealing rings are soft and smooth, they are easy to care for, when they need to be cleaned, you can simply add a little cleansing and wash them with warm water