NUK First Choice+ Flow Control Teat: helps the transition to independent drinking The special NUK First Choice+ Flow Control teat lets babies control the flow themselves when they are drinking. No matter if they want to drink quickly or slowly or if whatever you are feeding is thin or thick. Just as the baby likes it. In addition, the teat is also leak-proof. This is because the innovative Y-opening of the teat only opens when your baby is sucking and widens depending on the sucking strength of your baby. Together with the NUK Anti-Colic Air System, this ensures a controlled drinking flow.