A mother's nipple adapts perfectly to a baby's mouth, that is why the new, improved NUK teats replicate a mother's nipple whilst breastfeeding. The feeling is not only pleasant for babies; the soft nipple easily takes on different shapes whilst also promoting the development of the mouth, lips and tongue. The NUK teat features the special, orthodontic, asymmetrical NUK shape, an extra wide lip support and new extra soft tip to fit baby's mouth perfectly, simulating breastfeeding as closely as possible - so true to nature that most babies hardly notice the difference. The NUK Teat also features the NUK Anti-colic Air System, which allows air to flow into the bottle through the improved vent, stopping baby swallowing air and helping to prevent colic.