Guitar String Action Ruler Gauge Tool Stainless Steel Measuring Kit Multi Function Guitar Luthier Accurate String Measurement for Electric Bass and Acoustic Guitar by AENMIL 100% brand new and high quality Fraction/Decimal/ Metric conversion chart on back Made of durable Stainless Steel ,Convenient , compact credit-card sized rule With conversion chart of string action at 12th fret printed on one side Suitable for string instruments such as guitar, bass, mandolin, banjo, etc