Designed in conjunction with breastfeeding experts, the revolutionary new Tommee Tippee Closer to Nature Easi-vent teat mimics the natural flex, movement and softness of a mum's breast, to make switching between breast and bottle easier than ever before.The unique shape of the Closer to Nature Easi-vent teat encourages your baby's natural feeding action so that switching between breast and bottle becomes second nature.With its unique Easi-vent anti-colic valve (which you can actually see working) the Closer to Nature Easi-vent teat is at the heart of an entire breastfeeding support system which also includes a breast pump, sterilisers and accessories specially created to help you combine breast and bottle feeding.