this Breast Milk Storage Starter Set makes breast milk storage and feeding easier by eliminating the need to transfer milk. Attach a six ounce storage container to your breast pump and express directly into the container. Cover with leak proof lid and then store in refrigerator or freezer. Simply replace the sealing disc with a nipple for easy feeding - no need to transfer milk from container to bottle. All Avent nipples and spouts can be used with the storage containers. Dishwasher safe. Avent 6-Ounce Breast Milk Storage Starter Set, BPA-Free, 10-Pack BPA-free and dishwasher safe Leak-proof, twist-on lid for safe storage in the fridge or freezer The outer tread twist-on lid ensures a secure seal and no leakage Protect breast milk by expressing, storing and feeding from the same container No need to transfer breast milk Write-on cups and lids so that you can conveniently track dates and contents Stackable cups and lids for easy storage