The device resembles a harp and can be played, but it lacks any vibrating strings. That is, where there are supposed to be strings that can be vibrated with a finger, there is nothing. Instead, several red laser beams shine down from the upper arm of the harp, acting as strings. When the player's finger interrupts the path of each of these beams, a musical note is produced.
Using a fog machine, the path of the laser beams is made visible by the fog created.