These pre-sterilised milk-storage bags from Spectra are double walled and freezer safe. The bags are completely Bisphenol-A free for extra safety when feeding your baby. The bags can be easily resealed to prevent any contamination or leakage. The scale on the front of the bags allows you to see how much milk it contains. The bags are self-standing, so they can easily stand upright in your fridge or freezer.