These plastic breast milk storage bags come pre-sterilized, and are easy to carry around. In fact, they come in a tissue-style dispenser, making them easy to access and store. Each bag stores up to 6 ounces, or 180 milliliters of milk, and seals tightly to preserve freshness. Bags lay flat in the freezer saving plenty of space for more milk or other foods. Milk transfers easily from bag to bottle with no spillage. A tab above the fill area lets you write the express date, volume of milk, and the name of your child (in case you are handing it off to a busy daycare provider for feedings) on the bag without worry that you may puncture and contaminate your milk with ink