1.Fit for electric guitar, Bass , acoustic guitar,mandolin,banjo,etc. 2.With conversion chart of string action at 12th fret printed on one side. 3.With scale for string height, for saddle slot depth and for nuts saddles and pole pieces. 4.Made of metal which is stable,,beautiful and widely used. 5.From inch fractions, to inch decimals, to metric in increments. Specifications: Material: metal Color: Silver Application: electric guitar, bass , acoustic guitar etc. Unit: mm/ in Scale for string height: 0.01-0.14in / 0.25-3.50mm Scale for bridge saddle slot depth: 0-0.875in / 0-20mm Scale for nuts saddles and polepieces: 0-0.75in / 0-20mm Ruler size: 8.9 x 5.1cm / 3.5 x 2in (length x width) Ruler weight: 28g / 0.99oz Package Contents:1 x String action ruler Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.