Instruct: Classify an Amazon review into positive or negative sentiment.
Query: Comfortable and High Quality Sound.

A convenient device. With the body of the device sitting behind the ear, it is surprisingly very comfortable to wear. It sits solidly and doesn't jostle in the ear when walking or if moving your head from left to right. The sound quality is crisp and clear and it does a great job filtering background noise. I've even gone as far to asked the party that Im talking to on their option of the sound quality on their end. Many we're surprised that I was talking on a Bluetooth device. Among my friends, I seem to pick the worst headsets known to mankind. With the Voyager 510, I'm on the right track now.