NUK Smooth Flow Bottles offer a solution to colic for bottle feeding with a unique nipple design that lets your baby control the flow rate. The adaptable Smooth Flow nipple adjusts the flow based on your baby's suction strength, ensuring a colic-free feeding experience every time. With the Safe Temp temperature indicator, you can easily tell when the milk is too hot with just a quick glance. The blue thermometer fades and reappears to let you know when the milk is safe to drink. Please note, bottle colors may vary.