This is our 5th box was music, so the internal springs jump one after the other (we use mobile 2-3 times every baby diaper change). Only a box marked "Nattou" took a long time (it still works) but it dropped more than a meter and the external hook is broken; So we take this brand fingers crossed. Strangely this hook it is narrower, making it very difficult box to install and remove the mobile (no risk that mobile falls).
3 stars (I like) become 4 (love) if it is my last box but she will never have 5 (it is perfect) because I find its sound not quite rounded
