I have a Belkin FM transmitter and I am less then satisfied with it. Seem hard to find a clear frequency some times. A clear frequency can become distorted a few miles down the road. I was told by someone that the adapter that plugs into a tape cassette works better because there is a direct connection that eliminates most of the interference.

I wound up returning the Dynex universal transmitter, and exchanged it for a DLO transmitted that's built specifically for my Zen Vision M. The transmitter is actually attached to the end of the connection to the lighter, so the only wire I have is to the player.

I drove from Allentown to Harrisburg and back (about a 90 minute drive each way), and had great sound the entire trip. I was amazed. Even when I played some solo piano tracks (where there'd be the greatest risk of hearing static and interference), I didn't hear any. So I definitely found a great product.