It's faster to use than any ruler, and stays parallel to the fingerboard—much easier than trying to hold a ruler perpendicular to a rounded fret. • Fret slot depth (unbound fingerboards). String Action Gauge.
The Stew Mac USA #0670 Metric String Action Gauge Luthier Tool String Height Tool is perfect for skilled luthiers and music instrument technicians who require a precise instrument for measuring and adjusting string action height.
