Twist Active-Latch Nipples come in three bottle nipple sizes and snap directly onto Kiinde Twist Pouch Breast Milk Storage Bags, so you can feed your baby directly from the bag and skip the hassle of transferring milk from bags to bottles. The silicone bottle nipples come in three flow rates to match your baby s growing needs. Part of Kiinde s breastmilk collection, storage and feeding system, these bottle nipples promote deep, wide, natural latching and help with the transition between bottle and breast. The Active-Latch Nipples can also be used for formula feeding.