To achieve a perfect fit, the Thalia Capo comes with multiple interchangeable fretpads so that you can match the fretboard radius of your specific guitar. Check out our Fretboard Radius Database to find a table that lists common fretboard radii used by major guitar makers. If you do not find your specific brand and model guitar below you can google your guitar make/model plus the words "fretboard radius"; if that doesn't work you can use the manual method.