String action gauge ruler: comes in 8.9 x 5.1 cm/ 3.5 x 2 inch, pocket-sized, double sided, marked metric and imperial, etch printing on double sides, will not fade, accurate and clear to measure string height, bridge height, nut slot depth, bridge slot depth and pickup height | Understring radius gauge: come in sizes of 7.25/ 9.5/ 10/ 12/ 14/ 15/ 16/ 17/ 20 inch, fretboard measured in radians, and radians to adjust the strings piano code, obtain accurate measurements of your instrument's fretboard radius, saddle radius, nut radius from either the upper or the bottom radius surface | Guitar luthier tool set: this luthier tool set includes 9 understring radius gauges and 1 double side string action ruler, comprehensive for setting up your guitar, convenient to carry and store | Longer-lasting material: all the guitar measuring tools are made of stainless steel with smooth edges that have no burrs, anti-rust and scratch-prevent, durable to serve your guitar for a long term | Simple and precise: this set of luthier tool is made for keeping your string instruments in almost the top playing condition, helping you to set up your instrument with precision so that you can pluck at the right chords without stressing your fingers