String Action Ruler Gauge Tool for Electric Bass and Acoustic Guitar Useful conversions, long lasting etched printing Pocket-sized, a lot of info on a tool of this size With conversion chart of string action at 12th fret printed on one side With scale to measure string height, bridge saddle height, saddle slot depth, pickup polepiece height, fret slot depth and nut height Perfect accurate action measurements for string instruments such as guitar, bass, mandolin, banjo, etc