I bought this product after having lost 2 of another manufacturer's Bluetooth headsets, both of which had fallen off my ear on separate occasions. Except for their cost, the aforementioned products were not a great loss . . . they mangled voice commands to the point where I gave up even trying. Typically, I would say, "Call Nanette Cell," and the phone would respond with, "Did you say 'send text message to Ralph home?'" After several similar tries I found myself shouting at the phone, "NO YOU IDIOT! Go #*%!yourself!"In any event, the Plantronic 510 was like a gift from heaven. It's mechanical design keeps it secured on and in my ear, the audio is excellent, and my voice commands now work at about a 95% level. And the cherry on top was that it cost MUCH less than my previous units, which carried the imprint of one of the largest, most respected companies.The Plantronics engineers are entitled to a salute for this one.Fred