I received 6 bottles as a gift, 3-8 oz, 3-4 oz. These bottles were great, didn't leak unless mostly tightened. I bought additional bottles to have and also for grandparents who will be watched my son. The new bottles are fine until the nipples are fastened on. The plastic ring is totally different, I could tell when I opened the package. They're a little sharper edged, have a dimple in the top of them and are leaky when not tightened completely. Very disappointed. Not only is it inconvenient while shaking to mix and wasting formula/making a mess, it's also difficult to crank open in the middle of the night. Add to that older people having to crank these closed and reopen them makes these very disappointing. If I could find other glass bottles by another brand I would try them. Totally changed in two months time is disappointing and a waste of money.