The Kiinde Twist Active Latch Nipples bundle includes slow flow (2 pack) and medium flow (2 pack) innovative nipples designed to provide a seamless transition between bottle and breastfeeding. The nipples teach and reward a deep, wide natural latch to discourage lazy latching techniques, helping relieve colic in breastfed infants. The 1-piece patented nipple design attaches directly onto Kiinde's Twist Pouches so you can feed expressed breast milk directly from the pouch without any transfers or risk of spills. Simply drop the pouch into the Twist Squeeze Natural Feeding Bottle frame and pop on the nipple. As baby feeds, the pouch collapses to eliminate air ingestion that causes gas, fussiness, and upset tummies. With no threads or leaks, the nipples are easy to clean as a single piece. They are top rack dishwasher and steam sterilizer safe. The reusable nipple cases double as protective bottle covers for on-the-go. All materials are BPA, PVC and phthalate free. This bundle allows you to start with the slow flow nipples and easily transition your baby to medium flow as needed. Pair the nipples with Kiinde's full system of breast milk storage bags, pump adapters, organizers and warmers for the ultimate hassle-free way to collect, store, prepare and feed breast milk.