D'Addario Fingerboard Appliqu&eacute; Optic, 3/4 Size Violin, 304mm scale Fits a 3/4 size violin or 13" viola Optic - dot markers and visible lines provide additional visual cues Promotes proper finger placement using a tactile approach Adds subtle frets to the instrument, making it easier for players of fretted instruments to cross over to violin Installs in minutes and is easily removed