Mr. Di Zhao was the chief engineer at one of the major flute manufacturers in Boston until he decided to start his own flute company. All Di Zhao instruments are made with careful attention to precision. All instruments are made to achieve smooth key action, fast response, and excellent resonance. All Di Zhao instruments have been tested and adjusted by Di Zhao like the top professional flutes in the U.S. Hand-cut headjoints with undercuts and overcuts make the sound quality full and easy to play. All instruments are tuned to pitch 442.