Professional Guitar Tools: Guitar luthier tool set includes: 32 Blades Steel Feeler Gauge Dual, 9 Understring Radius Gauge, 1 String Action Gauge Ruler, 2 Fingerboard Guards and 1 Grinding Stone in a velvet bag9 Understring Radius Gauge: Stainless steel material, set of 9 including: 7.25", 9.5", 10", 12", 14", 15", 16", 17" and 20" radius, luthier tools for guitar and bass setupHigh Quality: Made of stainless steel with rounded off edge, anti rust, prevent scratch or cutting, durable and long service lifeWide Usage: Suitable for measure all kinds of electric guitar, electric bass, acoustic guitar, acoustic guitar, electric box guitar fretboard measured in radians, radians to adjust the strings piano code32 Blades Feeler Gauge: Steel Feeler Gauge measuring range: 0.0015 inch/ 0.04 mm to 0.035 inch/ 0.88 mm, light oil covered to prevent rust and stick, thumb screw is easy to use for blade removal and protection