Faster and More Accurate Tuning for Your Acoustic Graph Tech's Ratio Acoustic Tuned Machine Heads offer a revolutionary new experience in ensuring your guitar is tuned more quickly and accurately than conventional tuner designs. Each tuner in the set boasts a custom gear ratio that makes each machine head react the same — roughly one full turn per whole tone. Because each string reacts the same, not only is tuning a more pleasant experience, but nailing alternate tunings is a much faster process. Graph Tech's mission statement is "to improve your playing experience." They've nailed it with the Ratio Acoustic Tuned Machine Heads.Graph Tech's Ratio technology Though it's a simple idea, Graph Tech's Ratio technology completely changes the way you tune your guitar. All six strings are outfitted with gear ratios that ensure you attain the same response from your wound low E string as you do your unwound high