The Medela Pump & Save Breastmilk Bags helps save time by making your ability to pump or pour into bag for fast, easy breastmilk storage. The Oxygen barrier preserves & protects breastmilk nutrients, making the no-leak, easy-to-close zipper top and no-spill, stand-up bottom Medela Pump & Save Breastmilk Bags an easy choice.