For Most Guitars - All kinds of electric guitar, electric bass, acoustic guitar, acoustic guitar, electric box guitar fretboard measured in radians, and radians to adjust the strings piano code | Accurate Measurement - Obtain accurate measurements of your instrument's fretboard radius using the bottom radius of the gauge | Easy to Use - Fast, accurate bridge saddle adjustment. These come in the most popular fingerboard radius and make it easy to measure the radius from either above or below the strings. | Set of 9 including: 7.25", 9.5", 10", 12", 14", 15", 16", 17" and 20" radius | A must have for bass guitar maintain and adjustment