Made of high-quality BPA-free plastic, food-storage containers not only offer an airtight and watertight seal, but they?re also very durable. The containers can withstand temperatures ranging from -4 degrees F to 210 degrees F (-20? C to +120? C), making them suitable for use in the freezer, reheating food in the microwave, and can be cleaned in the dishwasher. The base and lid should not be used in the oven, or under grill elements.