We discovered this terrific product after months of trying other units. I had a Samsung that worked pretty good but the plastic ear hooks broke off almost immediately. I bought an Emerson at a discount store. It worked pretty good but I lost it. Later, my parents decided to buy me a Bluetooth and asked me to pick one out. We had heard good reports on the Motorola models sold by Amazon, but decided to go with the Plantronics. It looks good and works very well. It stays on my ear! It excels whenever there is background noise and it pairs well with my Motorola KRZR phone. Sometimes it will lose connection if I cover over the phone with my hand or arm. People on the other end of the conversation say that it's clear and free of static or noises most of the time. I was using a Motorola hands-free type Bluetooth in my car, but the quality was lousy. If you get out of range with the 510, it will automatically re-connect to the cell phone if you don't wait too long. My dad ended up buying all of us the Plantronics Voyager 510 and we are satisfied. I recommend the 510 to anyone who needs a good unit for a fair price.