Features: Made of high-quality LDPE and PET material, BPA free, which makes it environmental-friendly, safe and healthy to use. Pre-sterilised, very healthy to store and freeze breast milk. Double leak-proof sealing strips for secure storing and easy closing and opening. Self-standing bag, after using it to hold breast milk, you could stand or flat it in the refrigerator, it won't take much space, very convenient to use. The exterior of the storage bag is designed to conveniently record the date, time and volume of breast milk storage, the blue colored data is for clear and fast reading.