Abstract: In one embodiment a musical instrument, having a plurality of strings, a plurality of frets situated transverse to the strings and playable as with a cylindrical steel bar member slidably positionable along and against said strings, has an elongated mirror positioned generally parallel to the strings and generally perpendicular to the frets as to provide a visual indication to the player as to how accurately the player has positioned the steel bar member with respect to a selected fret; in another embodiment of the invention, the steel bar member itself carries a mirror surface thereby enabling the said elongated mirror to be dispensed with.