Bests & Worsts Reviews from Amazon

We were excited to buy these but then became extremely infuriated when they randomly leaked about 20 percent of the time. Usually at 3:00 AM in the dark! Check it out: after trying all kinds of fixes found online, from undertightening the lid assembly, to lining up the vents to markings on the rim, we figured out our issue: we were not assembling the bottle correctly before feeding. Specifically, the nipple is meant to be pushed (or more easily, tugged) nearly all the way through the white rim component, so that the surface of the outer nipple transitions smoothly to the white plastic of the rim. See the three attached photos for the visual cues for proper alignment. Looking back on it, this beautiful smooth transition is clearly shown in all the high resolution product photos. Our mistake was assuming that the nipple needed to sit lower down inside the white plastic rim. Our mental model involved thinking that the outder edge of nipple needed to be compressed against the rim by the mouth of the bottle, and so our previous attempts at fixing the leaks (adjusting the tightness of the lid, mainly) never worked. If the nipple is not pushed up all the way flush with the top surface of the rim piece, the milk will just flow happily around the edge of the nipple during feeding. Sometimes it will gush out immediately. In our case, a teaspoon of milk would pool up in the rim until feeding finished, and then spill out on the baby, onesie, bed, our feet, the floor... I haven't seen anyone else mention this approach. Meanwhile, there are plenty of people complaining that none of the other solutions address the leaking. I think this is not so much a design flaw as a communications issue. We were tearing our hair out over our fancy glass bottles until, in frustration, one of us went back to basics and watched a YouTube video demonstrating how to use the things. It was actually a sales video and the lightbulb went on when the salesman put everything back together and was careful as a last step to tug the nipple up through the white rim piece, rather than just pushing it halfway through as we were doing before. These bottles are great if they are put together properly! Otherwise they will leak all over! DUH, MAN!!! If this explanation helped you, please upvote this so that more people can learn the solution to this maddening user error!