Duopro Convertible Headphones with Noise Canceling Microphone. The most versatile headset ever! The innovative Plantronics DuoPro offers all day comfort and best-in-class sound quality. The H171N is the convertible model with noise-canceling microphone. New ergonomic innovations offer unsurpassed comfort and the patent-pending anti-twist boom ensures perfect microphone placement. Two-year warranty.