Lansinoh's #1 selling breastmilk storage bags are ideal for storing, freezing, and protecting precious breastmilk. Built super strong, Lansinoh's breastmilk freezer bags come with a double zipper seal to prevent leakage and reinforced double sealed side seams for ultimate protection. Presterilized for safe storage plus BPA and BPS free. Easy to use and saves time by pumping directly into the bag. Pump directly into bags with any Lansinoh breast pump, milk storage bags attach directly to pumping set. For use with other pumps (fit most Medela, Ameda and Evenflo pumps), attach Lansinoh Pump Adapter to the pumping set and bags, adapters sold separately.