This is a very poor toy. The instructions are poorly translated into English. They are not at all clear. For example they do not explain how to use the "spring terminals". The diagrams add very little value. There is no help available if the thing doesn't work, which in my case it didn't. The components, especially the coil's wires, are very fragile and the wires' colours, which are critical, are barely distinguishable. From an educational point of view the thing is useless as there is no explanation as to what is happening, what the various components do or why they should be linked together in the way they are. There is no explanation as to how a crystal radio works, in particular why it doesn't need a battery.
A complete waste of money and a bitter disappointment. This would completely discourage any kid from ever building anything from a kit of parts him/herself ever again.