Product name:Steel String Action Gauge Ruler Product size about : 16*10cm/6.2*3.9in Product color: As shown in the figure Product material:Stainless steel product features: Guitar Setup and Adjustment. This is a handy little item that is great for helping guitarists, luthiers or guitarists set up their guitars for improved playability. Inches and Millimeters. The tool includes a 12-fret string action scale, string height scale, bridge saddle slot scale, and nut, saddle and pole piece scales in inches and millimeters; all markings on the scale are very clear and easy to read. Versatile. The tool is great for helping measure string height, pickup height, bridge saddle height, saddle slot depth, fret slot depth and nut height, pickup pole piece height; for electric guitar, acoustic guitar, bass or other stringed instruments. Comes with a User Guide. A string action setup guide sheet is included with the product, along with an English paper card with instructions. Helpful and easy to use. With a string action gauge, your guitar will be more accurately set up and less hit-and-miss. Precautions: 1. As we all know , the different computers display colors differently, the color of the actual item may vary slightly from the following images. 2. If you feel difficult to choose the size, you can contact us at any time. We will give you some suggestions, but for your reference only. Shipment includes: 1 pc Steel String Action Gauge Ruler