The accordion is played both solo and in ensemble. Accordions for solo performance have a keyboard on the right side that is the same as an organ’s. On the left side there are a number of keys and buttons that can control the harmonics, so it can easily play all kinds of chords. Though accordions for solo performances have a complete set of functions, they are much more expensive than ensemble instruments. Moreover, the buttons on such an accordion produce only subtle differences in tone. Thus, most children’s bands use ensemble accordions. These are identical to accordions for solo performance except that they lack the keys and buttons on the left-hand side. The style of the accordion keyboard is the same as that of the piano or the organ, but narrower and shallower. Accordions differ in sizes, as well as in registers. Since the instrument is played hanging on the chest from a belt, it cannot be too big or it will put too much pressure on the chest and stomach. Thus, the keyboard cannot have more than 41 keys.