Breastmilk Storage Bags have been developed specifically for the freezer, and when stored flat, take up less space and defrost quicker. The Lansinoh Breastmilk Storage Bags make storing, warming and transporting your breastmilk easy and convenient for you. Reinforced side seams with double zipper seal to ensure no loss of breastmilk. Each bag had a tab above the fill area to eliminate potential puncture of the bag. The medical grade bags are produced without using plasticisers, meaning there is no risk of any harmful substances leaking into your breastmilk.