oh and also i found the little rubber thing kept splitting and it shouldnt be like that as the new ones i kept getting didnt have a slit!
There quite pants really, didnt find they helped at all with colic, Dr Browns all the way!
They are ment to have a slit, all new ones need to be pinched to opne the slit up if the slit isnt opened then the teats collapse and makje the whole anti colic part pointless as its creating presure within the bottle