Willow Spill-proof Milk Bags: 3 Pack Total Of 144 Bags Holds 4 Oz. Per Bag | Self-sealing Storage Bags, Recyclable & Bpa Free | Breast Feeding Essential For The Willow Pump

Our Milk Bags have a one-way valve so milk comes in and doesn't come out. They are already sealed when you remove them from the pump, making them one-use only. This also means you can pump and store in the same bag without having to transfer your milk. You can store it in the fridge or freezer until you're ready to use the milk. Our Milk Bags are single use and should not be reused.