They were working ok until I washed the clear soft plastic top on (the sipper). I noticed there was dirt under it, between the soft part and the hard plastic part of the lid, and that could only be cleaned if the top (the clear part with the sipper) came off and was washed separately, which seemed ok I guess, after all Nuby should've known that it can get really nasty if we don't wash the lid parts separately. After I did that I but it back exactly like the way it was before and did all the adjustments but they kept on leaking! They leak so bad it's impossible for my baby to use it without having water pouring from everywhere. And the price wasn't too cheap either. Now I have to throw them away because they're just useless.