Hosco H-RG2 Universal FretboardGauge
Hosco H-RG2 Universal FretboardGauge, Fingerboard Gauge, For fretboard radius, string position and fret height, Suitable for the 6 most common radii: 7.25"", 9.5"", 10"", 12"", 14"", 16"", String height scale: 0.2 - 3.0 mm, Scales for measuring the height of fret crowns: 0.6 - 1.5 mm