I bought this piece for the echo cancellation. (I did read the instructions) I haven't found it yet. The people/listeners on the other end of the line continously complain about the echo. They hear me as if I was in a tunnel. While you can use it in both ears, you will still have to completely plug it into your ear to keep it in place. The hook around the ear is just to prevent it from falling out of your ear and onto the ground as it does not hold the apparatus in place for a clear sound/connection. I have it paired with an LG-VX8300 and it does not maintain the connection. I keep on dropping calls. The sound is continously transferred to the phone itself leaving me driving down the road with an earpiece in one ear and the phone in the other. The battery time is less than the promised two hours.The pros: small, small, small....