If you are using the Thrive System with our nfant® Tracker App, you will be guided through the process of selecting the right flow rate for your baby’s age and feeding needs. As a general rule of thumb, nipples with a slower flow rate (such as our Extra Slow Flow Nipple or Slow Flow Nipple) are best for newborns, premature and breastfeeding babies. Read more about How to Pick the Right Flow Rate for Your Baby in our Feeding 101 Help Center.