I have used these with all of my kids. All of them loved them. Their little mouths just didnt want big nipples, you can find these at target. Another plus is when they start holding their own bottle these are so light and they don't overfeed themselves tring to get it all down. If they fall asleep with one of these bad boys their shape is a plus. Sometimes they will stand up when you drop um. If you leave the nipples in the sink wet too long they get all gross and change color. Oh and if you premix you formula...the top mark at the rim is 4 oz. So they do have the capacity to use 2 scoops of formula. Just don't put it in first, mix it first and then put it in. All in all, love um and their cheap. I'm definetly a fan.