Made of materials that do not contain BPA,* Ergonomic, safe and personality design.* Can be used in microwave, refrigerator.*Durable and beautiful material.Lock & Lock?containers are made with a special plastic called Polypropylene – which can withstand temperatures from -20?C to 120?C. This means it’s safe for storing hot foods or liquids and reheating in the microwave . The containers are also very easy to clean and durable – they won’t break or crack with normal use.