The melodica is a wind instrument. It is played by blowing air through the mouthpiece and simultaneously pressing one or more keys at the keyboard.The modern form of the instrument was probably invented by Hohner in the 1950s or 1960s. They are widely in use in music education.
It is one of the few polyphonic wind instruments, since unlike a saxophone or a clarinet you can play multiple notes at the same time.
My metal cased Hohner melodica 'piano 26'.
Since you control the sound by your blowing, it produces a sound which differs from the standard electronic keyboard. It’s a small and easy controllable instrument which can be used if you want to add some flavour to your songs.