Quoting Hikaru Katsu:" maybe my friend was putting them together wrong "
Quoting Soon 2B Mom of 2:" If you put the little blue thing on wrong, forget it, or screw the top on wrong they leak. I did it all the time I would always just go back and adjust it, and they worked great."
Quoting Hikaru Katsu:" did your baby ever have gas problems with them? the platex bottles i use work just fine, but if i find any other brand that works better i'd be willing to try them. "