Relaxed and safe feeding thanks to NUK Temperature Control Feature ! Checking the temperature before feeding the little ones is important. Knowing exactly if the right temperature is reached can be a challenge for parents. That's why NUK baby bottles with Temperature Control function were developed.This is a function to help prevent feeding too hot contents to your baby. NUK Premium Choice baby bottles now feature the new NUKTemperature Control Indicator that looks like a thermometer, is located within the graduation marks on the bottle and the temperature of the bottle contents makes it change colour which will help parents as an additional check to ensure the the temperature is not too hot. If the content temperature is too hot, the normally blue indicator will turn white. Ideally, the content for feeding should have body temperature of (37°C) and corresponds to the mean blue tone on the indicator. NUK Anti-Colic Air System ensures a natural flow when baby drinks to prevent colic.