Pumping breastmilk is a vital function for new mothers. Keeping the breastmilk safe and ready to store for future use helps to keep your baby healthy. This is why Medela has created these double-zipper and hygienically sealed breastmilk ready to use storage bags. The Medela Breast Milk Storage Bags have been hygienically pre-sealed with durable material and double-zipper protection to prevent leaking. These bags safely store breastmilk in the freezer, fridge, or when traveling. These ready to use breastmilk storage bags are constructed from a durable, double-layer material with a built-in double zipper seal to keep your breastmilk safely stored in the fridge or freezer.