The First Years breastflow bottles have a feeding mechanism that needs suction and compression just like regular breastfeeding. These baby feeding bottles encourage your child to latch on and mimic their natural motions while nursing. The First Years bottles have 2-in-1 nipples that replicate the natural feel of breastfeeding. The soft outer nipple lets your baby position his or her tongue as they would during feeding. The inner nipple lets your child control the flow of milk. These 5-ounce baby feeding bottles make it easier for babies to alternate between breastfeeding and bottle. The bottles are designed with nipple vents and wide necks. The First Years bottles come in a 3 pack and are suitable for newborn babies and young infants. Plus, they"re BPA-free and CPSC certified.