This product is great. I first learned about this when my sisterinlaw bought it. then a few weeks ago my brothers baby was having problems. they were using advent bottles. i kept on telling her about dr browns and she didn't believe me. Till one day she got fed up and finally went to babiesrus with me and i made her buy it. Now she wishes she used this from the beginning. IT's a must. no more gas for the baby .she's great now.