When you design a new music box or toy, the most important factor you need to consider is ,what is your music box toy powered by? Spring Driven musical movement, Wind up by special keys or pull-string device. There are some pictures as following. Crank Operated musical movement, hand operated by a crankshaft. There are some pictures as following.

The answer is “The standard 18 note models”. The reasons as below: 1.With the simplest structure,can be manufactured by automatic equipment, and the cost can be lower than other models. 2.With the richest tune resources. 3.The quality is stable because of the simple structure.