The martin string action gauge is an essential tool for musicians who want to ensure their stringed instruments are properly set up. Made from durable metal this versatile gauge offers both standard and metric measurements. Designed for use on all stringed instruments from guitars to violins the gauge allows you to achieve the best possible sound quality and playability. From the leaders in world class acoustic tone comes a must have tool for maintaining proper setup. The string action gauge provides suggested 12th fret action measurements allowing you to adjust their instruments action to the ideal height for optimal performance. With the ability to go lower if no buzzing is present this gauge ensures that your instrument will always be ready to deliver the perfect sound. Set up like the pros and enjoy the improved playing experience that comes with a finely tuned instrument.