•Ultra Preemie - 35% slower flow rate than Dr. Brown's Preemie Flow nipple
•Preemie - Slowest-flow nipple works with internal vent system for paced feeding
•Newborn- Faster flow than preemie but slower than level 1 can be a happy middle ground
•Level 1 is ideal for feeding newborns
•Level 2 is for babies 3 months and older
•Level-3 is ideal for feeding infants 6 months and above
•Level 4 is ideal for feeding more aggressive eaters
•Y-Cut nipples are ideal for babies 9 months and above