These disposable breast milk storage bags are made of food-grade, BPA-free PE material, which is safe and non-toxic. Sterilized by ethylene oxide, they are ready for direct contact with breast milk. The bags feature clear volume markings and sections for writing name, date, and time to help organize milk by collection time. The double-track seal prevents leaks, and the stand-up design allows for easy storage and access. Suitable for refrigeration or freezing, they are an ideal choice for breastfeeding mothers.