The NUK First Choice+ Baby Bottles with Temperature Control show at a glance when the right drinking temperature is reached. The scale on the bottle changes colour depending on the temperature of the contents. If too hot, the normally blue indicator turns white. Important: NUK Temperature Control is intended as an additional check. Therefore, the temperature should still be checked manually before actual feeding. To check the temperature of the contents, put a few drops on the inside of your wrist.