Many mothers like to have extra bottles of breast milk on hand to be able to manage milk production and make the best use of all the milk. Medela's breast milk bottles have been designed for safe long-term storage of breast milk. You can pump the breast milk directly into the bottles and store it there. In addition, you can feed the baby from the same bottle. The bottles are made of safe plastic that is designed to preserve the good properties of breast milk. This way you can store the breast milk safely in the fridge or freezer. The clear, colorful millimeter markings make it easy to see exactly how much milk you have expressed. The bottles also have screw caps so that they do not leak while they are stored in the fridge or freezer, or during transport when you are out and about, for example.Medela's bottles are shatter-free. They can be used with all Medela breast pumps and teats.The breast milk bottles are dishwasher and microwave safe and made from bisphenol A (BPA) free material.