Features: 9pcs Radius gauges come in sizes of 7.25" 9.5" 10" 12" 14" 15" 16" 17" 20". For electric guitar, electric bass, electric guitar, acoustic guitar fretboard. Easy to measure the radius from either above or below the strings, and come with Pin Puller. Using the matching top radius of this gauge to determine the proper height adjustment for the bridge saddles.