Electronically operated apparatus in the nature of a box, housing automatically-operated controls for operation of visual/aural indicators to be associated with a musical instrument for use as an aid to the teaching or learning the playing of a musical instrument.
Electronically operated apparatus in the nature of a box, housing automatically-operated controls for operation of visual/aural indicators to be associated with a musical instrument for use as an aid to the teaching or learning the playing of a musical instrument.
Electronically operated apparatus in the nature of a box, housing auto...
