Nut Slotting Gauge The Nut Slotting Gauge quickly and precisely measures the heights of the strings over the first fret, so you can file nut slot depths more accurately than ever before That means easier, more consistent playability, that you can custom-tailor to individual instruments and playing styles No more guesswork or "eyeballing" the string heights, and no more searching for elusive combinations of feeler gauge. It features an easy to read dial indicator with adjustable zero point, and accurate to .001" that can be rotated and locked, 360 degrees for easy viewing The machined brass base fits flat over the fret and strings for a more accurate reading And rests securely on the fingerboard.