1. High quality 2. Obtain accurate measurements of your instrument's fretboard radius using the bottom radius of the gauge 3. Then use the matching top radius of this gauge to determine the proper height adjustment for saddles 4. These come in the most common fingerboard radii and are easy to measure the radius from either above or below the strings 5. Use these to accurately set up your guitar bridge saddles to match the fingerboard radius Ruler side: Can be used for gut string guitars, electric guitars (raise or lower string height), acoustic guitars, and bass guitars (including six-string bass guitars) to adjust string spacing. This tool set is suitable for measuring all kinds of electric and acoustic guitars, electric basses, and fretboards measured in radius to adjust string height Usage: These guitar luthier tools are ideal for guitar technicians and guitarists to maintain and repair their instruments efficiently, reducing string buzz; Suitable for electric guitar, acoustic guitar, bass, banjo, and folk guitar 9: 7.25 inch, 9.5 inch, 10 inch, 12 inch, 14 inch, 15 inch, 16 inch, 17 inch, 20 inch Color: Silver Material: Stainless Steel Package Contents: 9 x Radius gauges (shaped rulers) 1 x String height ruler Only the above package content is included; other products are not included Note: Light reflection and different displays may cause the color of the item in the picture to appear slightly different from the real thing. Measurement allowance is +/- 1-3 cm