Lansinoh Breastmilk Storage Bags are uniquely designed for moms to save time by pumping directly into the storage bags. Moms love the convenience of Lansinoh Breastmilk Storage Bags. They stand up for easy refrigerator storage and lay flat for space-efficient freezer storage. Nursing mothers have trusted Lansinoh for more than 30 years to provide safe and effective products to make breastfeeding easier.Moms can pump directly into the breast milk bags using a Lansinoh pump or attach the Lansinoh pump adapter to pump directly into many other common pump brands. Lansinoh pump adapters are sold separately. Lansinoh milk storage bags come pre-sterilized and have a patented double Click 'n' Secure seal to prevent leakage. With reinforced side seals and a double-sealed gusset, Lansinoh breast milk storage bags are the strongest available and are BPA and BPS free.IMPORTANT! Ensure your Lansinoh Breastmilk Storage Bags have white and purple flowers and a white line above the logo. If your bags do not have this design, it is not compatible with pumping directly into the bag.