【Usage Range】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】Fast, accurate bridge saddle adjustment,obtain accurate measurements of your instrument's fretboard radius,saddle radius nut radius from either the top or the bottom radius surface | 【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 | 【Understring Radius Guages】Stainless steel material,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 | 【100% Satisfactory After-Sales Service】- If you have any problems while receiving our product or after that, please contact us through emails at any time. We will offer you a quick response within 24 hours and give you the most satisfied solution.