Natural Response Newborn Gift SetSupports baby's individual drinking rhythm A nipple that works like a breast 3 Bottles Bottle brush Nipple releases milk when baby actively drinks The Natural Response Nipple works with your baby's natural feeding rhythm, making it easy to combine breast feeding and bottle feeding. The nipple has a unique opening which only releases milk when the baby actively drinks. So when they pause to swallow and breathe, the milk pauses too. Natural latch on