Precise string action gauge in .010" (ten thousandths of an inch) number increments, and .005" line increments, super accurate guitar setup! Laser etched through the black surface, deeply into the stainless metal. Fret height/fret wear gauge in .005" increments. No more fumbling with calipers, straightedges or feeler gauges. The 3 unequal length sides are CNC machined, precision diamond honed and polished. The silver square on the bottom corner of the gauge, under .010 thick, which allows it to slip into each nut slot - including the narrow high e slot. Material: Stainless Steel Specification: Simply rest the thin corner into the bottom of each nut slot - and the other end across to the 2nd fret, then measure the gap as the gauge passes over the 1st fret. It's never been easier to zero in on the perfect string height as it leaves the nut. Size Chart: L x W x T: Approx. 85.7 x 54 x 0.52mm/3.37 x 2.13 x 0.02 inch Package Includes: 1 Piece Guitar String Action Gauge Note: Due to the difference between different monitors, the picture may not reflect the actual color of the item. Due to manual measurement, there may be 1-2cm error in size.