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.