The mobile is nice, has 4 different hanging toys.
The music comes from a wind-up music box embedded in a leaf-shaped green plastic link between the top arm and the lower 4-way toy hanger. Fully winded, lasts about a minute or two. The wind-up mechanism also makes the mobile turn around.
Toys are made of a plastic body and wings made of cloth. The are hung by a string and a knot, so they can be removed for cleaning/washing. No velcros.
The top arm has a crib attachment mechanism that should work with most cribs. A big plastic screw and a big nut. Unfortunately, my 1-month-old son's crib has rounded bars and the attachment slips around them and tilts down under its own weight.
We are keeping it because we'll be soon moving him into a bigger crib that has square bars that will solve this issue.
Some of the other issues I found are that the box is way too big, due to the way things are packed inside (everything zip-tied onto a dummy board with holes). Seems that the manufacturer wanted its product to be easily appreciated through a rather big window on the box's side (for shelf-teasing purposes, I guess).
The bad news is that assembly is still needed, and on top of that, having to untie all those zips is rather annoying.
Having bought it online, paying shipping & handling for a box two-times-too-big with a window on it seems pointless.
Also, the assembly procedure is not undoable. Meaning that once you assemble the top arm (2 pieces snapped toghether) they won't come apart, unless you break them. That's stated in the booklet, not making this up, I promise! So it won't fit back in the box should you have to return it. Bummer. Keep in mind if not 100% sure about it or looking for a pain-free return policy.
Anyway, the mobile in itself is very nice, and got it way cheaper than comparable mobiles in baby shops around Barcelona, where we live.