DESIGNED FOR ACOUSTIC AND ELECTRIC GUITARS WITH RADIUSED FRETBOARDS. MICROMETER TENSION ADJUSTMENT ASSURES BUZZ-FREE IN TUNE PERFORMANCE AT EVERY FRET. MICROMETER TENSION ADJUSTMENT ASSURES BUZZ-FREE IN TUNE PERFORMANCE AT EVERY FRET. AIRCRAFT GRADE ALUMINUM CONSTRUCTION. WORKS FOR 6 OR 12 STRING ACOUSTIC AND ELECTRIC GUITARS; ALSO AVAILABLE IN A CLASSICAL GUITAR VERSION. ALSO AVAILABLE IN BLACK, SILVER, AND METALLIC BRONZE.