I had major leaking problems with these bottles! It was extremely frustrating to wake up in the middle of the night and prepare a bottle and then have to begin to leak and start all over again! I called Playtex several times to tell them about the problem. Each time they sent me replacement bottles/parts and coupons for Playtex products. After about a month of dealing with the mess I finally called them back and told them the bottles were still leaking and that I appreciated all of their help but I would not be using their bottles any more. I wish I would have known before I had bought the whole set of bottles. Hopefully the word will get out there so other moms don't waste their time and money!