1、Guitar Measurement Set: Includes 3 pieces measurement tools, suitable for various electric guitars, electric basses, acoustic guitars, etc., measuring and adjusting strings and bridges in radians. 2、Foldable Feeler Gauge: Measuring range from 0.038mm (0.0015in) to 0.889mm (0.035in), commonly applied distance measuring tool for guitar gaps, and the Cr plated spindle is easy to clean. 3、Fretboard Radius Gauge: There are 9 different sizes of fretboard radius rulers, including 7.25 inch, 9.5 inch, 10 inch, 12 inch, 14 inch, 15 inch, 16 inch, 17 inch, and 20 inch, diverse and practical. 4、String Action Gauge: Both sides are marked with metric and inch scales, to measure the string height, bridge saddle height, saddle slot depth, pickup height, fret slot depth, and nut height. 5、Excellent Materials: These measuring tools are made of excellent stainless steel, which has good rust and erosion resistance. Glossy finish design that will not damage the instrument or your hands.