The Marxophone is a fretless zither

Guitar zither

The guitar zither is a musical instrument consisting of a sound-box with two sets of unstopped strings...

 that has four sets of chord strings (C major

C major

C major is a musical major scale based on C, with pitches C, D, E, F, G, A, and B. Its key signature has no flats/sharps.Its relative minor is A minor, and its parallel minor is C minor....

, G major

G major

G major is a major scale based on G, with the pitches G, A, B, C, D, E, and F. Its key signature has one sharp, F; in treble-clef key signatures, the sharp-symbol for F is usually placed on the first line from the top, though in some Baroque music it is placed on the first space from the bottom...

, F major

F major

F major is a musical major scale based on F, consisting of the pitches F, G, A, B, C, D, and E. Its key signature has one flat . It is by far the oldest key signature with an accidental, predating the others by hundreds of years...

 and D7

Chord (music)

A chord in music is any harmonic set of two–three or more notes that is heard as if sounding simultaneously. These need not actually be played together: arpeggios and broken chords may for many practical and theoretical purposes be understood as chords...

) to be strummed with the left hand and two octave

Octave

In music, an octave is the interval between one musical pitch and another with half or double its frequency. The octave relationship is a natural phenomenon that has been referred to as the "basic miracle of music", the use of which is "common in most musical systems"...

s of double melody strings, (Middle C

C (musical note)

C or Do is the first note of the fixed-Do solfège scale. Its enharmonic is B.-Middle C:Middle C is designated C4 in scientific pitch notation because of the note's position as the fourth C key on a standard 88-key piano keyboard...

 - C) which are struck by metal hammers activated by the right hand. The melody strings are tuned to the C major scale, making the instrument somewhat like a piano without any black keys.

The hammers are mounted on spring steel and produce a mandolin-like sound from repeated bouncing on the strings, hence the name mandolin-guitar-zither sometimes applied to the Marxophone.