This is a piano that can play without a pianist. It was most popular from 1900-1940; at that time phonographs were still crude. As the development of phonographs grew more sophisticated the player piano declined.
Most were powered via the feet with pump bellows, but a few were electronic. Most looked like a typical upright piano but had a mechanism to insert a sheet of music. This was known as a music roll and as the person pumped the bellows with his feet it would roll the music, and the piano keys would play according to the perforations in the music roll.
Music rolls were about 11 and 1/4 inches wide and usually 100 feet in length. Of course this was rolled up. Some music rolls merely struck the notes, while others had additional holes in them to control the piano pedals, the volume and accents and came close to reproducing the actual playing by a person.