The 9 stage is in the transition stage for babies going from completely dependent to learning to walk, talk and self-feed. Your baby is voicing likes and dislikes. The transition can be challenging, especially if you have tried other bottles without success.  For older babies the Minbie 9 teat is like being close to home with the familiar latch and feeding motion of breastfeeding. The Minbie teat offers superior support for the mother-baby breastfeeding bond and, by requiring babies to work for the feed with their instinctive breastfeeding technique it supports natural jaw development (which is important since much of human jaw development happens in the first four years). When you buy the Minbie 9 Months Advanced nipples, we recommend that you also purchase a pack of 6 Months Fast teats to help match your baby’s feeding rate currently. If your baby is progressing from our 6 Months Fast teats, then the 9 Months Advanced are the next size.