The celesta is a percussion instrument with a set of tuned steel bars struck by hammers, which in turn, are controlled by a keyboard just like a piano. It looks a bit like an upright piano.  Its range is from middle C up 4 octaves.

Probably the most well-known piece of music featuring the celesta is The Dance of the Sugar Plum Fairy from the Nutcracker ballet suite, by Tchaikovsky.