The package includes 1 Guitar Neck Notched String Measurement Ruler and 1 String Action Ruler. Perfect accurate action measurements for string instruments such as guitar, bass, mandolin, banjo, etc. | Guitar Neck Notched Straight Ruler - Made of stainless steel, rustproof, sturdy enough for your long-term use. Size: 16.5 x 1.45 x 0.13 inch, Weight: 230g. Dual scale design, works well with most guitar, specially suits for Gibson(24.75") and for Fender(25.5") electric guitars | Fritz Ruler - Made of high quality plastic, The ruler is double-sided, there is fraction, decimal, metric conversion chart on back.This guitar string action gauge ruler can measure string height, bridge saddle height, saddle slot depth, fret slot depth and nut height and accurately measure other setup adjustments. | The Neck Notched String Measurement Ruler is designed to check guitar neck straightness of the fretboard and frets. Fritz Ruler Use To Measure: Nut / String / Bridge / Pickup Pole Piece / Saddle Height Plus Saddle Slot/ Fret Slot Depths | Excellent Luthier tool and essential for any guitar technician, or guitarist who wants to look after, maintain and repair their instrument themselves.