The Milkies Freeze is a convenient "first in, first out" breast milk storage system that fits right in your freezer. Simply collect your precious breast milk in any milk storage bag, and place the bag on the metal quick-freeze tray at the top of the Freeze. Once the milk is frozen, slip the bag into the Freeze storage system through the slot at the top, and the bag will fall to the bottom of the storage container. When you need to thaw a bag of breast milk to feed to your little one, pull a bag out from the bottom of the Freeze - that way you are sure to use the oldest milk first! The Milkies Freeze can store up to 60 ounces of breast milk. BPA and phthalate free!