I'm using these with the Dr. Brown's bottles for my late pre-term newborn. Originally she was using the level 1 nipple with the small Medela bottles that come with the pump. I then tried to move on to more "permanent" bottle with Tommee Tippee and that didn't work out (too much dribble). Eventually decided to use the Preemie nipple with the Dr. Brown's and it's been working out great.

My newborn was not premature, but was having a hard time with level one nipples. The flow was too fast and he didn't have to suck, the milk just poured into his mouth. I had to stop every 1/4 - 1/2 ounce and make sure he was swallowing or he would choke/spit up etc. Plus, I am breastfeeding and using bottles too, and he started to get lazy on the breast, I guess he was waiting for it to pour out like the bottles...

So I switched to these premie nipples and all is good. He has to work to get milk from the bottle and has gone back to nursing well. The flow is just right.

These are great. Perfect for preemies or other babies that need a slower flow.