2 Set Musical instrument accessories: 1 Set x T-shaped rulers & 1 Set x Guitar Electric Drill Plug Guitar Bass Electric Drill String Winder Plug Peg Puller Great for all guitars, banjos, and mandolins It feels good in your hands and operates smoothly and high quality, testing is fine colour:black + Silver Material:metal + Stainless Steel Guitar Electric Drill Plug size:2.4 x 6.6cm Fritz ruler side:Could be used for gut guitars, electric guitars (raise or lower string height), acoustic guitars,and bass guitars (including six string bass guitars) to adjust the string space.this tool set is suitable for measuring all kinds of electric & acoustic guitar, electric bass, electric box guitar fretboard that measured in radians to adjust the strings piano code. Usage: these guitar luthier tools are good gifts to guitar technicians and guitarists to maintain and repair their instrument themselves in a short time, reducing buzzing; Good tools for electric guitar, acoustic guitar, bass, banjo and folk guitar, etc. Set of 9: 7.25inch 9.5inch 10inch 12inch 14inch 15inch 16inch 17inch 20inch 1. 100% and 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 the bridge saddles. 4. These come in the most popular fingerboard radius and make it easy to measure the radius from either above or below the strings. 5. Use these to accurately setup your guitar bridge saddles to match the fingerboard radius. Package Contents: 9 x T-shaped rulers 1 x string height ruler 2 x Guitar Electric Drill Plug