MilkBank delivers the freshest breast milk possible, and fresh breast milk is the most nutritious for your baby. Clinical tests show that any level of oxygen exposure begins to spoil breast milk. For best nutrition, freshly pumped breast milk should be fed immediately or stored in MilkBank"s vacuum-sealed storage bottles for later feeding. Traditional storage methods, such as bags and bottles, trap harmful oxygen when sealed. This exposure to oxygen not only impacts the nutritional value, but can also distort the flavor, causing babies to reject stored breast milk. Choose Storage System or Storage Bottles 3-Pack (with 2.5 oz or 5 oz. bottles) Vacuum Storage System includes: 1-vacuum pump, 3- storage caps, 1- 2.5 oz storage/feeding bottle, 2 - 4.5 oz storage/feeding bottles, 1 - outer insulated bottle with Stage 1 nipple & dome. Vacuum Storage Bottles come with 3 botttles and caps. Protects vital nutrients and flavor Perfect for refrigerator or freezer, store up to 6 months Use the same bottle for storage Guaranteed leak proof Dishwasher safe, top rack Made of Polypropylene, Silicone, and ABS BPA free