Instruct: Classify the given review into positive or negative sentiment.
Query: Good for first 2 months and a nightmare thereafter

These bottles are well recommended but I recommend everyone out there to NOT buy them. I called the company complaining about the continuous leaking and they said I was screwing them on too tightly. Whatever! These bottles ruined several outings for us to the point where I am throwing them all out (I have about 30 - we have twins) and vow to never use them again. They are junk. The problem is, when you wash the nipples in the dishwasher (which is recommended by Avent) the shrink with time. Save your money and your frustrations!!!!!