The Closer To Nature Medium Flow Teats are designed in conjunction with breastfeeding experts.The revolutionary new easi-vent teat mimics the natural flex, movement and softness of mum's breast, to make switching between breast and bottle easier that before.The unique shape encourages your baby's natural feeding action so that switching between breast and bottle becomes second nature.Specially designed to help reduce air bubbles in the milk and to encourage a good latch-on at the teat to help reduce the risk of baby ingesting air during feeding.Suitable for 3-6 months.