The Motorola Endeavor HX1 isn't an ordinary Bluetooth headset. Along with Motorola's CrystalTalk technology and a two-mic design, the HX1 features bone conduction technology with a special in-ear sensor for combating external noise that would otherwise trip up an external mic.
Very good audio quality; Excellent noise canceling; Stellar battery life.
Voice quality is ever-so-slightly behind the top of the class; Stealth mode degrades sound quality to other callers