Breastmilk Storage Bags Lansinoh's one of the best selling breastmilk storage bags are ideal for storing and freezing precious breastmilk. With reinforced side seals and a double-sealed gusset, Lansinoh bags are the strongest breastmilk storage bags available. BPA and BPS free. Now, Pump directly into bags 2 ways: Using Lansinoh pump – Attach bag to expression set and pump directly into bag. Using most standard neck pumps - Attach adapter to expression set and pump directly into bags. Adapters sold separately. Important: Ensure your Lansinoh Breastmilk Storage Bag has white and purple flowers and a white line above the logo. If your bag does not have this design, it is not compatible with pumping directly into the bag.