NUK teats is my first choice when I decided to breastfeed and bottle feed for my baby. It was recommended by my friend. Well, I must said I made the right decision as it is well accepted by my baby and there is no confusion of nipple when I swith to direct breastfeed or bottle feed. There is a small hole in the teat which is the anti-colic system, it helps to prevent colic by reducing the amount of air swallowed. You will hear the air flow sound from the teat when the baby is drinking the milk. This silicone teat is soft and well fit to my baby's mouth as well. It helps improve the jaw development and makes the baby's teeth growing neatly as it was specially designed in orthodontic shape. Sometimes I can just switch to other bottle (for drinking water purpose) but still using the NUK teat as the anti colic system is designed on the teat. Now they have the improved designed (in the pic, left) which has more texture. I like that NUK will keep improving their product from time to time so that is why I used it for all of my 3 children since they were born.