Long enough I bought several bottles, which unfortunately does not keep all tight. The Nalgene absolutely holds tight. Our daughter (2.5 years old), it can also open and close all alone and loves them dearly. The drinking opening is significantly smaller than, for example a bottle of mineral water, but it is so large that is drunk not only reasonable and suckled tröpfenweise. We always comes only still water in the bottle. Carbonated goes well, but then not do so fully and open carefully, can aufploppen jerky when opened by the pressure otherwise the shutter. If the child keeps the bottle tightly over his face it could then hurt something. To me, in any case under no bottle more. This is now our 2nd small, the first has been forgotten in the holiday, it was terrible, "Wähähhä my Flaaaasche ....". So quickly ordered a new, now the world is back in order. The bottle is also larger, so that my 14-year-old likes to go to school. In the cleaning, I would like to touch briefly. The bottle can be cleaned in the upper basket in the dishwasher. That's really great, no unpleasant odors and really clean. (With horror I still think of the SIGG bottle my great, which was often times left lying. When juice it starts very quickly to bum and to stink, then this narrow teat part, which can not be cleaned properly ..... bah !) This bottle is worth the money!