AENMIL Pocket-sized Faster and Accurate String Action Gauge Ruler Stainless Steel Guide Setup Guitar Measuring Luthier Tool With Conversion Chart of String Action at 12th Fret Printed on one Side 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