1、[32 Blade Feeler Gauge] With a measurement range from 0.04mm to 0.88mm (0.0016 to 0.035in), coated with light oil to prevent rust and sticking, the wing nut is easy for blade removal. 2、[Versatile Radius Gauge] This guitar radius gauge set features 9 different sizes, from 7.25 inches to 20 inches, suitable for setting up guitars and basses to your specific needs. 3、[String Action Ruler] The included string action ruler gauge allows accurate measurement of string height, saddle height, saddle slot depth, pickup pole height, fret slot depth, nut height. 4、[Grinding Stone and Guard Set] The guitar grinding stone is designed for polishing nuts and frets, while the fretboard protector prevents scraping or damage. 5、[Safety Materials] Made of stainless steel and plastic, with rounded edges, rust and erosion resistance, will not scratch or injury your hands or fretboard and frets. 6、[Wide Application] The guitar luthier tool set is perfect for string instruments such as electric guitar, electric bass, wooden guitar, acoustic guitar, electric box guitar, etc.