This bottle holds in principle what it promises and is leak-proof. But only when the slider is closed at the top. As it is so with young children, they discover something new, then fingers continuously around it. Slide on and slide to slide on and slide on ... Well, and then can no longer speak of leakproof you. It injects the open often a fountain of the beverage through the area. In addition, you should know that it only works perfectly with non-carbonated beverages. Carbonated water or tea. Should work well for example. If you compress the tube (which children also like to try) has one with carbonated drinks like to a small fountain. Since fun is inevitable. I would not buy the bottle again. For us it is not really suitable. But since the quality is okay, I admit still 3 stars.
