I've had my 510 for two years and just lost it while on vacation this past week. Boy did I ever miss having it. The ease of use and noise-canceling feature makes this unit almost perfect and still deserving of a five star rating. Good thing for me that as technology marches on, prices drop. I paid almost eighty dollars for my first one. Today, I'm getting the same thing here on Amazon for less than half that amount. Don't waste time looking elsewhere for a better price. I just wasted a full hour-plus comparing prices and as of right now, the best price WITH FREE SHIPPING is on Amazon. Way to go guys!! B T W - I do NOT work for Amazon or Plantronics. Just another average Joe like the rest of you trying to help save some time. Thanks again Amazon Dot Com.