Features1. These handy covers are made from super-stretchy silicone.2. They are circular in shape but pliable enough to seal even odd-shaped containers.3. The tops are made from bpa-free, food-grade plastic.4. They are microwave and dishwasher-safe.5. They are also heat-resistant to 450 f, so reheating foods is never a problem.6. Save on expensive, disposable plastic wrap, and save money on food bills by storing scrumptious leftovers for another mealNoticeSturdy stretch lids is made of high quality silicone, can be used for a long time. Heat resistance from 40 freezing) up to 400 . Safe for Oven or Fridge.Warming tips:1. Lids are completely dry or they will not stay in place.2. When you are using it in Microwave or Oven,do not completely seal container would be better. Because the expanding heat and pressure from container, may result in damage or injury.Read moreHow to use it 1.Place half of the lids over one edge of the container.Start on the side closet to your body.2.Stretch the other half of the lid away from you,inching your way around the bowl.3.Stretch,then press the top of the lid while pulling the tabs to create a vacuum seal.4.Pull the sides to ensure a perfect fit.Firstly, the silicone lids can create an airtight seal with the containers that they are covering.Secondly, silicone lids are good for most surfaces and materials.The stretchable silicone lids may stick tighter on a shaking container, but flat silicone lids are more airtight in the long run.Silicone stretch lids is flexible to fit different size and shape container, and remain good shape after being not used and stored.These stretch lids are made of sturdy and stretchable silicone, reusable and will not warp or leak.Flexible Size:2.8"(will stretch to 3.5")3.7"(will stretch to 5")4.5"(will stretch to 6")5.7"(will stretch to 8")6.5"(will stretch to 9")8.3"(will stretch to 11")