Silicone stretch lids are made of high-level grade silicone, soft texture, durable, non-toxic which is 100% Phthalate, Lead, Plastic and BPA free. You can use the stretch lids all time without worrying your family health. Stretchy food lids help you keep the fruits, vegetables, drinks and other foods fresh, Keep spill and oder free, and also avoid food spills in microwave oven. ②Silicone lids food covers are better than plastic wrap or silver foils.Making it stackable and space efficiency in the refrigerator. Note: Don't seal the container when heated in the microwave. These silicone food cover are stretchable and durable,Can be stratchde doubled size as originally and can match mulitiful container without deformation.