Lansinoh Breastmilk Storage Bags are built super strong, featuring a double zipper seal and reinforced double sealed side seams for ultimate protection. Ideal for freezing and protecting breastmilk. Presterilized and BPA/BPS free. Pump directly into breastfeeding bags 2 ways: 1. Using Lansinoh breast pumps, attach bag to expression set and pump directly into bag. 2. Using most standard size pumps: Use the Lansinoh Pump Adapterto pump directly into bags.Adapter sold separately. Fits most Medela, Ameda, and Evenflo pumps. Key Features Built super-strong for storing, freezing, and protecting your breastmilk Pump directly into bag using your Lansinoh pump, or most major pump brands using our pump-into-bag adapter (sold separately) Presterilized with a tamper-evident, fully sealed tear-away top for safety Includes a large write-on label at the top plus a convenient pour spout Directions Pour breastmilk into the bag or pump directly into the bag up to 6oz max. Remove excess air and seal completely, then lay flat to freeze. To thaw, place the sealed bag in warm tap water. Please see additional instructions below and or inside the box. Use only as directed.