Dr. Brown’s Breastmilk Storage Bags are built for durability to store and protect your precious breastmilk.Dr. Brown’s Breastmilk Storage Bags are built for durability to store and protect your precious breastmilk. The self-standing bag features a leak-proof double zipper seal, marks for accurate measurement, and a labeling area for indexing and organizing. Bags are pre-sterilized for cleanliness.