?The Carman Bear Breastfeeding Bag 30 Pieces Milk Bag Dairy Breast Collection Bag Storageare perfect for storing and freezing milk for later. It is very easy to connect to the breast pump. They are coated and treated specially to block out air and moisture outside, keeping the expressed milk in fresh condition. The bags can be sealed tightly to prevent any contamination or leakage. The scare on the storage bags allows you to see how much milk has been expressed. The pre-sterilised bags are double-walled and are freezer safe. The bags can be stored flat in the freezer, which take up less space for more storage. The bags themselves are made from a medical grade, food-safe polyethylene, and no harmful substances can leak into the breastmilk when stored in the bags.