The StewMac Nut Slotting Ruler is a precision tool used by luthiers and guitar technicians to accurately measure and set the depth of nut slots on stringed instruments. It helps ensure that the string heights above the first fret are correct, which is crucial for achieving optimal playability and intonation. Key Features: Precision Measurements: Allows you to gauge the exact string height above the first fret for proper nut slot depth. Dual Scales: Usually comes with both metric and imperial mea