The NUK Breast Milk Container was created to keep breast milk in the best possible condition. The container can be used with all NUK Electric Breast Pumps as well as for all NUK First Choice Teats. NUK Breast Milk Containers help you store, freeze, warm and even feed the milk without any re-filling. The container can be frozen for up to 6 months. Since the container can be stored for a long time, you can write the date in the space provided to keep track of how long the milk has been frozen. The container can be used repeatedly and it can also be boiled.