I finally can hear my audiotapes without interference!
After purchasing over 3 fm transmitters and either returning them or throwing them out, I purchased the Monster RadioPlay and love it!! The sound is clear with little or no interference over radio stations. When I drove through Hagerstown, Maryland, I heard a little static but the sound from the audiotape was strong enough to block radio interference. (The previous fm transmitters cut out altogether as radio stations took over.) This fm transmitter does not require full volume to maintain contact unlike my previous transmitters that sounded muffled under full volume. Although the station choices are limited, I found that I could remain with the same radio station as I commute through PA, Maryland, and West Virginia on a daily basis. All three of my other fm transmitters required constant changing of stations!
I haven't tried this transmitter in populated areas outside of Hagerstown so you might want to check reviews from city commuters for fm transmitters that offer more stations. I highly recommend investing in this transmitter especially since you don't have to use batteries.

Monster Wireless FM transmitter
I got what I paid for! The major concerne on this type of equipment is interference, but in my case, is almost none, mainly in the city. I have recomended it to other people.
The functionality is great, simple. In my car is almost unnoticed that I have the transmitter on.

Works better than I first expected
I bought this because I had just gotten a new car with no cd deck and had one of those old cd transmitters. So I picked up this transmitter and it came one the game date it said it would which was nice. This really is one of those plug in and play devices. I unboxed it, went to my car, plugged it in, tuned my radio to the red lit up station and Music came out clear. I haven't had to try any of the other stations because the first one that I was set on worked well. The nice thing is that the plug in and the station transmitter glows red when the car is on and since my dashboard is red led colored it compliments it nicely.

If you are looking for a great way to play music in your car (with style that is ;) get this you will be happy.

Good sound and easy to use
The wireless radio transmitter works pretty well. I use it with my mp3 players as I travel for about 1.5 hours each way to and from work. I only have to change the radio station every once in a while as the station will get busy. The only thing it kind of annoying is the lack of a method to attach the cord to anything. But sound quality is usually pretty good as long as the cord does not fall.

couldn't ask for a better fm transmitter for 9$
owned it for about 3 weeks and works perfect it's hard to find a station not in use sometimes but that's going to happen with any transmitter.